... of a decrease in membrane excitability during the winter. Subsequent measurement of intracellular Ca 2+ activity using Fura-2 microspectrofluorometry confirmed a reduction in action potential activity, including duration and action potential profile, in neurons isolated during the winter. These studies...

... cerebral cortex. Our results show that an acute reduction in temperature from 20 to 5°C decreases membrane potential, action potential width and amplitude, and whole-cell conductance. Importantly, acute exposure to 5°C considerably slows membrane repolarization by voltage-gated K + channels. Exposing...

... activity typical for primary pacemaker of the heart, with smooth transition from SDD to action potential (AP) upstroke was found in a circle region at the base of the leaflets of the SAV ( Lukyanov et al., 1983 , 1986 ; Haverinen and Vornanen, 2007 ). Trautwein and Zink (1952) provided classic...

...Varshinie Pillai; Leslie Buck; Ebrahim Lari ABSTRACT Goldfish are one of a few species able to avoid cellular damage during month-long periods in severely hypoxic environments. By suppressing action potentials in excitatory glutamatergic neurons, the goldfish brain decreases its overall energy...

... (5H fish), on in vivo and spontaneous heart rate ( f H ), electrocardiogram, ventricular action potential (AP) shape and duration (APD), the background inward rectifier ( I K1 ) and rapid delayed rectifier ( I Kr ) K + currents and ventricular gene expression of proteins involved in excitation...

... in March (‘winter-acclimatized’). At a common test temperature of 7.5°C, action potential (AP) was shortened by both winter acclimatization and cold acclimation compared with summer acclimation; however, winter acclimatization caused a greater shortening than did cold acclimation. Shortening of AP...

... remained mostly quiescent, action potential frequency (AP f ) of the stellate neurons increased 68-fold. Furthermore, the GABA A receptor reversal potential ( E ­ GABA ) was determined using the gramicidin perforated-patch-clamp method and found to be depolarizing in pyramidal (−53.8 mV) and stellate...

... and the duration of atrial and ventricular action potentials (APs). Prolonged exposure to new thermal conditions induces compensatory changes in ion channel expression and function, which usually partially alleviate the direct effects of temperature on cardiac APs and heart rate. The most heat-sensitive molecular...

... temperature changes, thermal sensitivity of cardiac excitation in a eurythermal teleost, the roach ( Rutilus rutilus ), was examined. Excitability of the heart was determined from in vivo electrocardiograms and in vitro microelectrode recordings of action potentials (APs) from winter and summer roach...

... Acartia tonsa elicited fast (∼20 ms) animal-like action potentials accompanied by rapid contraction of the cell to avoid predation. We have shown that the sensory mechanisms of Favella sp. are finely tuned to the type, location, and intensity of stimuli from prey and predators. Fig. 7. Bioelectrical...

... of I Na was reflected as a low BPT for the rate of action potential upstroke in vitro (21.7±1.2°C) and the velocity of impulse transmission in vivo (21.9±2.2°C). These findings from different levels of biological organization strongly suggest that heat-dependent deterioration of Na + channel function...

... resting metabolic rate: estimated at 5–7% in fish to 20% in humans ( Mink et al., 1981 ). The high energetic cost is primarily due to the maintenance of membrane potentials, generation of action potentials and synaptic transmission (e.g. Attwell and Laughlin, 2001 ; Lennie, 2003 ; Niven and Laughlin...

... for correspondence (e-mail: holly.shiels@manchester.ac.uk ) 10 5 2006 © The Company of Biologists Limited 2006 2006 action potential Na + -Ca 2+ exchange l -type Ca 2+ channel K + channel I Ca I Kr I K1 sarcoplasmic reticulum (SR) temperature fish heart caffeine...

...Steven D. Buckingham; Declan W. Ali SUMMARY Larval somatic muscle of the zebrafish, Danio rerio , like that of some other organisms, responds to a sustained depolarization with one, and only one, action potential. Here, we report computer simulations, using the NEURON simulation programme...

... initiation of action potentials in response to stimulation by the MC motor neuron. Loss of cca-1 function decreases the chance that excitatory input from MC will successfully trigger an action potential, and reduces the ability of an animal to take in food. Intracellular voltage recordings demonstrate...

...-inactivated at–30.4 mV, and completely inactivated within 100 ms of depolarization. The inward currents of inner fibres were half-activated at –7.3 mV and half-inactivated at –74.5 mV and completely inactivated within 5 ms of depolarization. Inner muscle fibres were found to support action potentials,while...

... cells could be distinguished from non-bombykal-sensitive cells in each trichoid sensillum because the bombykal-responsive cell always generated the action potentials of larger initial amplitude. The bombykal cell, which was recorded at a defined location within a distal flagellar annulus, can resolve...

... two additional aspects of pharyngeal behavior. Serotonin decreases the duration of the pharyngeal action potential and enhances activity of the pharyngeal M3 motor neurons. Gramine, a competitive serotonin antagonist, and octopamine have effects opposite to those of serotonin: gramine and octopamine...

... and statistical analysis is given in Tables 1,2,3and in Fig. 3. SQ0.2Hz, square pulses at a frequency of 0.2 Hz;SQphysiol, square pulses at physiological frequency;APphysiol, action potential at physiological frequency. The peak amplitude of I Ca increased with temperature (Figs 2B , 3A ). The charge...

...Joshua J. C. Rosenthal; Francisco Bezanilla SUMMARY To determine which physiological properties contribute to temperature adaptation in the squid giant axon, action potentials were recorded from four species of squid whose habitats span a temperature range of 20°C. The environments of these species...