Authors: Yoshihiko Kito Hikaru Suzuki
Publish Date: 2007/01/18
Volume: 454, Issue: 2, Pages: 263-275
Abstract
The effects of temperature on the generation of pacemaker potentials recorded from myenteric interstitial cells of Cajal ICCMY distributed in the mouse small intestine were investigated using intracellular recording techniques In response to increasing temperatures in the range of 26–40°C the frequency and maximum rate of rise dV/dt max of pacemaker potentials were increased while their duration was decreased The resting membrane potential and amplitude of the pacemaker potentials were not affected by change in temperature Elevation of temperature decreased the amplitude duration and rise time of unitary potentials generated spontaneously during intervals between the pacemaker potentials Metabolic inhibition KCN and iodoacetic acid decreased the frequency of pacemaker potentials with no alteration to the amplitude and dV/dt max Cyclopiazonic acid 3 μM an inhibitor of the internal Ca2+ pump abolished pacemaker potentials in lowtemperature conditions 29°C but not at hightemperature conditions 38°C These results suggest that the primary and plateau components of pacemaker potentials have different temperature sensitivities the primary component is highly temperaturesensitive and is activated at higher temperatures while the plateau component is formed by activation of temperatureinsensitive mechanisms The results also suggest that the mitochondriainduced intracellular Ca2+ handling system seems to be involved in the initiation of the generation of pacemaker potentials but not in their configurationThe present experiments were supported partly by a GrantinAid for the Scientific Research C from the Ministry of Education Culture Sports Science and Technology MEXT of Japan to H S No 14570044 Ichihara International Scholarship Foundation also provided support to YK
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