Journal of Physiology-London

Article	Citations
Regulation of glycolysis by the hypoxia‐inducible factor (HIF): implications for cellular physiology	383
Revisiting the Warburg effect: historical dogma versus current understanding	363
The ARRIVE guidelines 2.0: updated guidelines for reporting animal research	175
The anaerobic threshold: 50+ years of controversy	158
Mitochondrial lactate metabolism: history and implications for exercise and disease	100
HIITing the brain with exercise: mechanisms, consequences and practical recommendations	94
Infiltration of intramuscular adipose tissue impairs skeletal muscle contraction	91
Lactate in contemporary biology: a phoenix risen	87
Ketogenic low‐CHO, high‐fat diet: the future of elite endurance sport?	70
Intra‐gastrointestinal amyloid‐β1–42 oligomers perturb enteric function and induce Alzheimer's disease pathology	69
Effects of e‐cigarettes and vaping devices on cardiac and pulmonary physiology	68
Hepatic stellate cells in physiology and pathology	63
COVID‐19 is getting on our nerves: sympathetic neural activity and haemodynamics in young adults recovering from SARS‐CoV‐2	62
Drp1 knockdown induces severe muscle atrophy and remodelling, mitochondrial dysfunction, autophagy impairment and denervation	62
Silent hypoxaemia in COVID‐19 patients	59
Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability	56
Inter‐hemispheric inhibition sculpts the output of neural circuits by co‐opting the two cerebral hemispheres	56
Neuromuscular junction instability and altered intracellular calcium handling as early determinants of force loss during unloading in humans	54
In vivo recordings from the human vagus nerve using ultrasound‐guided microneurography	54
Nitric oxide is fundamental to neurovascular coupling in humans	53
Low‐volume high‐intensity interval training for cardiometabolic health	51
The envelope protein of SARS‐CoV‐2 increases intra‐Golgi pH and forms a cation channel that is regulated by pH	50
Functional architecture of the motor homunculus detected by electrostimulation	49
Sex differences in fatigability following exercise normalised to the power–duration relationship	46
The noradrenergic agent reboxetine plus the antimuscarinic hyoscine butylbromide reduces sleep apnoea severity: a double‐blind, placebo‐controlled, randomised crossover trial	46

Time‐of‐day dependent effects of contractile activity on the phase of the skeletal muscle clock	44
Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging	43
Lifelong voluntary aerobic exercise prevents age‐ and Western diet‐ induced vascular dysfunction, mitochondrial oxidative stress and inflammation in mice	43
Synergic control of a single muscle: The example of flexor digitorum superficialis	43
Zolpidem increases sleep efficiency and the respiratory arousal threshold without changing sleep apnoea severity and pharyngeal muscle activity	43
Mechanisms underlying selective coupling of endothelial Ca2+ signals with eNOS vs. IK/SK channels in systemic and pulmonary arteries	43
Genetic and epigenetic regulation of skeletal muscle ribosome biogenesis with exercise	42
Fitness and strength responses to distinct exercise modes in twins: Studies of Twin Responses to Understand Exercise as a THerapy (STRUETH) study	41
TRPV1 expressed throughout the arterial circulation regulates vasoconstriction and blood pressure	40
Estimates of persistent inward currents are reduced in upper limb motor units of older adults	40
Ca2+‐permeable AMPA receptors and their auxiliary subunits in synaptic plasticity and disease	40
Piezo1 channels mediate trabecular meshwork mechanotransduction and promote aqueous fluid outflow	40
Architecture and function of NMDA receptors: an evolutionary perspective	40
Passive stiffness of fibrotic skeletal muscle in mdx mice relates to collagen architecture	39
Coupling structure with function in acid‐sensing ion channels: challenges in pursuit of proton sensors	38
Internal carotid and brachial artery shear‐dependent vasodilator function in young healthy humans	37
Training with blood flow restriction increases femoral artery diameter and thigh oxygen delivery during knee‐extensor exercise in recreationally trained men	37
Pregnancy‐induced changes in β‐cell function: what are the key players?	36
Distinct features of calcium handling and β‐adrenergic sensitivity in heart failure with preserved versus reduced ejection fraction	36
Deficit in knee extension strength following anterior cruciate ligament reconstruction is explained by a reduced neural drive to the vasti muscles	36
The mechanisms of skeletal muscle atrophy in response to transient knockdown of the vitamin D receptor in vivo	35
Functional, proteomic and bioinformatic analyses of Nrf2‐ and Keap1‐ null skeletal muscle	35
Physiological and molecular sex differences in human skeletal muscle in response to exercise training	35
Anodal and cathodal tDCS modulate neural activity and selectively affect GABA and glutamate syntheses in the visual cortex of cats	35
Kir6.1‐dependent KATP channels in lymphatic smooth muscle and vessel dysfunction in mice with Kir6.1 gain‐of‐function	35
Positive allosteric modulation of NMDA receptors: mechanisms, physiological impact and therapeutic potential	34
E‐cigarettes and respiratory health: the latest evidence	34
August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data	34
Influence of sex on the age‐related adaptations of neuromuscular function and motor unit properties in elite masters athletes	34
Nicotinamide riboside supplementation does not alter whole‐body or skeletal muscle metabolic responses to a single bout of endurance exercise	33
Divergence of neuroimmune circuits activated by afferent and efferent vagal nerve stimulation in the regulation of inflammation	33
In vitro ketone‐supported mitochondrial respiration is minimal when other substrates are readily available in cardiac and skeletal muscle	33
Common synaptic input, synergies and size principle: Control of spinal motor neurons for movement generation	32
New insights into resting and exertional right ventricular performance in the healthy heart through real‐time pressure‐volume analysis	32
Autonomic control of cerebral blood flow: fundamental comparisons between peripheral and cerebrovascular circulations in humans	32
1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine	31
Mitochondrial dysfunction in placental trophoblast cells experiencing gestational diabetes mellitus	31
Encoding sound in the cochlea: from receptor potential to afferent discharge	31
Respiratory cerebrospinal fluid flow is driven by the thoracic and lumbar spinal pressures	31
The influence of aerobic exercise on mitochondrial quality control in skeletal muscle	30
Current research: effect of time restricted eating on weight and cardiometabolic health	30
The need for specificity in quantifying neurocirculatory vs. respiratory effects of eucapnic hypoxia and transient hyperoxia	29
Modulation of Kv3.1/Kv3.2 promotes gamma oscillations by rescuing Aβ‐induced desynchronization of fast‐spiking interneuron firing in an AD mouse model in vitro	29
Chronic cold exposure induces mitochondrial plasticity in deer mice native to high altitudes	29
Time restricted eating for the prevention of type 2 diabetes	29
Loss of Baiap2l2 destabilizes the transducing stereocilia of cochlear hair cells and leads to deafness	29
Age‐related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells	29
Spinal motoneurones are intrinsically more responsive in the adult G93A SOD1 mouse model of amyotrophic lateral sclerosis	28
Extracellular miRNAs as mediators of obesity‐associated disease	28
Step time asymmetry but not step length asymmetry is adapted to optimize energy cost of split‐belt treadmill walking	28

Contraction influences Per2 gene expression in skeletal muscle through a calcium‐dependent pathway	27
Peripheral chemoreflex contribution to ventilatory long‐term facilitation induced by acute intermittent hypercapnic hypoxia in males and females	27
Unchanged cerebrovascular CO2 reactivity and hypercapnic ventilatory response during strict head‐down tilt bed rest in a mild hypercapnic environment	27
Heterogeneity in subcellular muscle glycogen utilisation during exercise impacts endurance capacity in men	27
Peripheral chemoreflex control of fetal heart rate decelerations overwhelms the baroreflex during brief umbilical cord occlusions in fetal sheep	27
Effects of reciprocal inhibition and whole‐body relaxation on persistent inward currents estimated by two different methods	26
E‐cigarettes, nicotine, the lung and the brain: multi‐level cascading pathophysiology	26
Photoreceptor physiology and evolution: cellular and molecular basis of rod and cone phototransduction	26
Transcriptomic, proteomic and phosphoproteomic underpinnings of daily exercise performance and zeitgeber activity of training in mouse muscle	26
The correspondence between EMG and EEG measures of changes in cortical excitability following transcranial magnetic stimulation	26
Evidence for improved systemic and local vascular function after long‐term passive static stretching training of the musculoskeletal system	25
Localization of Na+ channel clusters in narrowed perinexi of gap junctions enhances cardiac impulse transmission via ephaptic coupling: a model study	25
Regulation of plasma volume in male lowlanders during 4 days of exposure to hypobaric hypoxia equivalent to 3500 m altitude	25
Direct evidence for decreased presynaptic inhibition evoked by PBSt group I muscle afferents after chronic SCI and recovery with step‐training in rats	25
Exertional heat stroke leads to concurrent long‐term epigenetic memory, immunosuppression and altered heat shock response in female mice	24
Locomotor muscle group III/IV afferents constrain stroke volume and contribute to exercise intolerance in human heart failure	24
Optical measurement of physiological sodium currents in the axon initial segment	24
On the role of skeletal muscle acidosis and inorganic phosphates as determinants of central and peripheral fatigue: A 31P‐MRS study	24
Modulation of information processing by AMPA receptor auxiliary subunits	24
Analysis of extracellular spike waveforms and associated receptive fields of neurons in cat primary visual cortex	24
Acute activation of bronchopulmonary vagal nociceptors by type I interferons	24
Time‐dependent changes in autophagy, mitophagy and lysosomes in skeletal muscle during denervation‐induced disuse	24
Single muscle fibre contractile function with ageing	24
Blood viscosity and its determinants in the highest city in the world	24
Orexin neurons and inhibitory Agrp→orexin circuits guide spatial exploration in mice	24
Vitamin D is an endogenous partial agonist of the transient receptor potential vanilloid 1 channel	24
Inhibitory control of active expiration by the Bötzinger complex in rats	23
Physiology of physical inactivity, sedentary behaviours and non‐exercise activity: insights from the space bedrest model	23
Inhibitory interneurons regulate phasic activity of noradrenergic neurons in the mouse locus coeruleus and functional implications	23
CaMKII activity contributes to homeometric autoregulation of the heart: A novel mechanism for the Anrep effect	23
Advancing respiratory–cardiovascular physiology with the working heart–brainstem preparation over 25 years	23
Biophysical and morphological changes in inner hair cells and their efferent innervation in the ageing mouse cochlea	23
Kv3.1 and Kv3.3 subunits differentially contribute to Kv3 channels and action potential repolarization in principal neurons of the auditory brainstem	23
Regulation of muscle and mitochondrial health by the mitochondrial fission protein Drp1 in aged mice	23
Myosin dynamics during relaxation in mouse soleus muscle and modulation by 2′‐deoxy‐ATP	23
Near‐infrared spectroscopy estimation of combined skeletal muscle oxidative capacity and O2 diffusion capacity in humans	23
Biochemical and structural basis of the passive mechanical properties of whole skeletal muscle	23
Towards a mechanistic approach for the development of non‐invasive brain‐computer interfaces for motor rehabilitation	23
Vascular calcium signalling and ageing	23
Biased auditory nerve central synaptopathy is associated with age‐related hearing loss	23
Hodgkin–Huxley–Katz Prize Lecture: Genetic and pharmacological control of glutamate receptor channel through a highly conserved gating motif	23
The beta2‐adrenergic receptor – a re‐emerging target to combat obesity and induce leanness?	23
Vesicle‐released glutamate is necessary to maintain muscle spindle afferent excitability but not dynamic sensitivity in adult mice	22
Brainstem inflammation modulates the ventilatory pattern and its variability after acute lung injury in rodents	22
NMDA receptors in axons: there's no coincidence	22
Abnormal skeletal muscle blood flow, contractile mechanics and fibre morphology in a rat model of obese‐HFpEF	22
Dysbiosis of the gut microbiome impairs mouse skeletal muscle adaptation to exercise	22
Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm	22
Abnormal placental CD8+ T‐cell infiltration is a feature of fetal growth restriction and pre‐eclampsia	22
Pathophysiological changes in inner hair cell ribbon synapses in the ageing mammalian cochlea	22
Skeletal muscle AMPK is not activated during 2 h of moderate intensity exercise at ∼65% in endurance trained men	22
Long‐duration spaceflight alters estimated intracranial pressure and cerebral blood velocity	22
Ketamine anaesthesia induces gain enhancement via recurrent excitation in granular input layers of the auditory cortex	22
Hypertrophied human adipocyte spheroids as in vitro model of weight gain and adipose tissue dysfunction	22
The effect of lifelong endurance exercise on cardiovascular structure and exercise function in women	22
Nutrient timing and metabolic regulation	21
Arterial carbon dioxide and bicarbonate rather than pH regulate cerebral blood flow in the setting of acute experimental metabolic alkalosis	21
Steady‐state sweating during exercise is determined by the evaporative requirement for heat balance independently of absolute core and skin temperatures	21
Inhaled nitric oxide improves ventilatory efficiency and exercise capacity in patients with mild COPD: A randomized‐control cross‐over trial	21
Spinal motoneuron firing properties mature from rostral to caudal during postnatal development of the mouse	21
Peripheral impairments of oxidative metabolism after a 10‐day bed rest are upstream of mitochondrial respiration	21
Fetal growth, birth size and energetic cost of gestation in southern right whales	21
Amyloid Beta42 oligomers up‐regulate the excitatory synapses by potentiating presynaptic release while impairing postsynaptic NMDA receptors	20
Intermuscular coherence analysis in older adults reveals that gait‐related arm swing drives lower limb muscles via subcortical and cortical pathways	20
Differential effects of motor skill acquisition on the primary motor and sensory cortices in healthy humans	20
Nitric oxide contributes to cerebrovascular shear‐mediated dilatation but not steady‐state cerebrovascular reactivity to carbon dioxide	20
Facilitation–inhibition control of motor neuronal persistent inward currents in young and older adults	20
Zona incerta neurons projecting to the ventral tegmental area promote action initiation towards feeding	20
Peroxisomal proliferator‐activated receptor α‐b deficiency induces the reprogramming of nutrient metabolism in zebrafish	20
Acid–base balance and cerebrovascular regulation	20
The suitability of high throughput automated patch clamp for physiological applications	20
Ageing and exercise‐induced motor unit remodelling	20
CrossTalk opposing view: NKCC1 in the luminal membrane of choroid plexus is outwardly directed under basal conditions and contributes directly to cerebrospinal fluid secretion	19
PKCε stimulation of TRPV1 orchestrates carotid body responses to asthmakines	19
Effects of short‐term unloading and active recovery on human motor unit properties, neuromuscular junction transmission and transcriptomic profile	19
Time‐restricted feeding combined with aerobic exercise training can prevent weight gain and improve metabolic disorders in mice fed a high‐fat diet	19
Modulation of cortical slow oscillatory rhythm by GABAB receptors: an in vitro experimental and computational study	19
Location, location, location: the organization and roles of potassium channels in mammalian motoneurons	19
Influence of blood flow occlusion on muscular recruitment and fatigue during maximal‐effort small muscle‐mass exercise	19
Interpreting ‘anti‐inflammatory’ cytokine responses to exercise: focus on interleukin‐10	19

Maternal exercise attenuates the lower skeletal muscle glucose uptake and insulin secretion caused by paternal obesity in female adult rat offspring	19
Glial amplification of synaptic signals	19
Exosome engineering for efficient and targeted drug delivery: Current status and future perspective	19
Correlation networks of spinal motor neurons that innervate lower limb muscles during a multi‐joint isometric task	19
Exposure to high fructose corn syrup during adolescence in the mouse alters hepatic metabolism and the microbiome in a sex‐specific manner	19
The effects of maternal position, in late gestation pregnancy, on placental blood flow and oxygenation: an MRI study	19
The role of mitochondria in metabolic disease: a special emphasis on heart dysfunction	19
Neuronal hypertrophy dampens neuronal intrinsic excitability and stress responsiveness during chronic stress	19
Biological validation of electron paramagnetic resonance (EPR) image oxygen thresholds in tissue	18
Maternal obesity causes fetal cardiac hypertrophy and alters adult offspring myocardial metabolism in mice	18
Biological sex, not reproductive cycle, influences peripheral blood immune cell prevalence in mice	18
GluN3A NMDA receptor subunits: more enigmatic than ever?	18
Evidence for multiple bulbar and higher brain circuits processing sensory inputs from the respiratory system in humans	18
Hypothalamic–vagal oxytocinergic neurocircuitry modulates gastric emptying and motility following stress	18
Presynaptic development is controlled by the core active zone proteins CAST/ELKS	18
Nitrate attenuates high fat diet‐induced glucose intolerance in association with reduced epididymal adipose tissue inflammation and mitochondrial reactive oxygen species emission	18
Functional development and regeneration of hair cells in the zebrafish lateral line	18
A role for neurokinin 1 receptor expressing neurons in the paratrigeminal nucleus in bradykinin‐evoked cough in guinea‐pigs	18
Junctophilin‐4 facilitates inflammatory signalling at plasma membrane‐endoplasmic reticulum junctions in sensory neurons	18
Blockade of 5‐HT2 receptors suppresses motor unit firing and estimates of persistent inward currents during voluntary muscle contraction in humans	18
Publications, replication and statistics in physiology plus two neglected curves	18
Optogenetic approaches to therapy for inherited retinal degenerations	18
Role of pattern recognition receptors and the microbiota in neurological disorders	17
Oxygenation pattern and compensatory responses to hypoxia and hypercapnia following bilateral carotid body resection in humans	17
The capillary fascicle in skeletal muscle: Structural and functional physiology of RBC distribution in capillary networks	17
Rapid volume pulsation of the extracellular space coincides with epileptiform activity in mice and depends on the NBCe1 transporter	17
Oxytocin receptors excite lateral nucleus of central amygdala by phospholipase Cβ‐ and protein kinase C‐dependent depression of inwardly rectifying K+ channels	17
Bugs, breathing and blood pressure: microbiota–gut–brain axis signalling in cardiorespiratory control in health and disease	17
Influence of iron manipulation on hypoxic pulmonary vasoconstriction and pulmonary reactivity during ascent and acclimatization to 5050 m	17
Divergent immunometabolic changes in adipose tissue and skeletal muscle with ageing in healthy humans	17
How does oxygen diffuse from capillaries to tissue mitochondria? Barriers and pathways	17
Enhancing responsiveness of human jejunal enteroids to host and microbial stimuli	17
Influence of the mode of heating on cerebral blood flow, non‐invasive intracranial pressure and thermal tolerance in humans	17
Abnormal cerebellar function and tremor in a mouse model for non‐manifesting partially penetrant dystonia type 6	17
Na+ is shifted from the extracellular to the intracellular compartment and is not inactivated by glycosaminoglycans during high salt conditions in rats	17
Circadian actions of orexins on the retinorecipient lateral geniculate complex in rat	17
Gut peptide regulation of food intake – evidence for the modulation of hedonic feeding	17
Feasibility of ventricular volumetry by cardiovascular MRI to assess cardiac function in the fetal sheep	17
Desmin prevents muscle wasting, exaggerated weakness and fragility, and fatigue in dystrophic mdx mouse	17
Increasing SERCA function promotes initiation of calcium sparks and breakup of calcium waves	17
An MRI approach to assess placental function in healthy humans and sheep	17
Adipocyte function and the development of cardiometabolic disease	17
Beetroot juice lowers blood pressure and improves endothelial function in pregnant eNOS−/− mice: importance of nitrate‐independent effects	17
The molecular mechanism of CFTR‐ and secretin‐dependent renal bicarbonate excretion	16
Electrophysiological significance of the interatrial conduction including cavo‐tricuspid isthmus during atrial fibrillation	16
Resilience of neural networks for locomotion	16
Modelling unitary fields and the single‐neuron contribution to local field potentials in the hippocampus	16
NAD+ and NAFLD – caution, causality and careful optimism	16
Remote ischaemic preconditioning – translating cardiovascular benefits to humans	16
Motor unit dysregulation following 15 days of unilateral lower limb immobilisation	16
Maternal but not fetoplacental health can be improved by metformin in a murine diet‐induced model of maternal obesity and glucose intolerance	16
What gets on the nerves of cardiac patients? Pathophysiological changes in cardiac innervation	16
Endocytic adaptation to functional demand by the kidney proximal tubule	16
Disproportionate loss of excitatory inputs to smaller phrenic motor neurons following cervical spinal hemisection	16
Rapamycin and mTORC2 inhibition synergistically reduce contraction‐stimulated muscle protein synthesis	16
Increased skin wetness independently augments cool‐seeking behaviour during passive heat stress	16
Naked mole‐rat brain mitochondria tolerate in vitro ischaemia	16
Vagus nerve stimulation activates nucleus of solitary tract neurons via supramedullary pathways	16
Intrinsic and synaptic mechanisms controlling the expiratory activity of excitatory lateral parafacial neurones of rats	16
Phenotyping heart failure using model‐based analysis and physiology‐informed machine learning	16
Muscle BDNF improves synaptic and contractile muscle strength in Kennedy's disease mice in a muscle‐type specific manner	16
Structural basis for positive allosteric modulation of AMPA and kainate receptors	16
The 70‐year search for the voltage‐sensing mechanism of ion channels	16
Regulation of cardiovascular health and disease by visceral adipose tissue‐derived metabolic hormones	16
Quantification of cardiac and respiratory modulation of axonal activity in the human vagus nerve	16
Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms	16
Placental fatty acid transport across late gestation in a baboon model of intrauterine growth restriction	16
Physiological roles of heteromerization: focus on the two‐pore domain potassium channels	15
Late gestation fetal hyperglucagonaemia impairs placental function and results in diminished fetal protein accretion and decreased fetal growth	15
A molecular signature defining exercise adaptation with ageing and in vivo partial reprogramming in skeletal muscle	15
‘Resistance is futile?’ – paradoxical inhibitory effects of KATP channel closure in glucagon‐secreting α‐cells	15
Sex differences in the sympathetic neurocirculatory responses to chemoreflex activation	15
Transcapillary PO2 gradients in contracting muscles across the fibre type and oxidative continuum	15
Preserved stem cell content and innervation profile of elderly human skeletal muscle with lifelong recreational exercise	15
AMP‐activated protein kinase activation in skeletal muscle modulates exercise‐induced uncoupled protein 1 expression in brown adipocyte in mouse model	15
Divergent splanchnic sympathetic efferent nerve pathways regulate interleukin‐10 and tumour necrosis factor‐α responses to endotoxaemia	15
Exercise training remodels subcutaneous adipose tissue in adults with obesity even without weight loss	15
Connexin 46 and connexin 50 gap junction channel properties are shaped by structural and dynamic features of their N‐terminal domains	15
Acute reductions in haematocrit increase flow‐mediated dilatation independent of resting nitric oxide bioavailability in humans	15
Tetraspanin‐7 regulation of L‐type voltage‐dependent calcium channels controls pancreatic β‐cell insulin secretion	15
Inflammatory gene expression during acute high‐altitude exposure	15
Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading	15
Cortical layer 6 control of sensory responses in higher‐order thalamus	15
Selective activation of BK channels in small‐headed dendritic spines suppresses excitatory postsynaptic potentials	15
Oxidant‐resistant LRRC8A/C anion channels support superoxide production by NADPH oxidase 1	15
Identification and classification of interstitial cells in the mouse renal pelvis	15
Neurovascular and cortical responses to hyperoxia: enhanced cognition and electroencephalographic activity despite reduced perfusion	15
Carbohydrate improves exercise capacity but does not affect subcellular lipid droplet morphology, AMPK and p53 signalling in human skeletal muscle	15
Contraction‐regulated mTORC1 and protein synthesis: Influence of AMPK and glycogen	15
Simplified method to quantify valve back‐leak uncovers severe mesenteric lymphatic valve dysfunction in mice deficient in connexins 43 and 37	14
Insulin‐stimulated glucose uptake partly relies on p21‐activated kinase (PAK)2, but not PAK1, in mouse skeletal muscle	14
A sodium background conductance controls the spiking pattern of mouse adrenal chromaffin cells in situ	14
Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men	14
Glucocorticoids regulate mitochondrial fatty acid oxidation in fetal cardiomyocytes	14
The current chemical biology tool box for studying ion channels	14