Temperature affects voltage-sensitive conductances differentially in octopus cells of the mammalian cochlear nucleus.
Temperature is an important physiological variable the influence of which on macroscopic electrophysiological measurements in slices is not well documented. We show that each of three voltage-sensitive conductances of octopus cells of the mammalian ventral cochlear nucleus (VCN) is affected differently by changes in temperature. As expected, the kinetics of the currents were faster at higher than at lower temperature. Where they could be measured, time constants of activation, deactivation, and inactivation had Q10 values between 1.8 and 4.6. The magnitude of the peak conductances was differentially affected by temperature. While the peak magnitude of the high-voltage-activated K+ conductance, g(KH), was unaffected by changes in temperature, the peak of the low-voltage-activated K+ conductance, g(KL), was reduced by half when the temperature was lowered from 33 to 23 degrees C (Q10 = 2). Changing the temperature changed the kinetics and the magnitude of the hyperpolarization-activated mixed cation conductance, g(h), but the changes in magnitude were transient. The voltage sensitivity of the three conductances was unaffected by temperature. The action of temperature on these conductances is reflected in the resting potentials and in the shapes of action potentials.
Cao
Xiao-Jie
XJ
Department of Physiology, University of Wisconsin, Madison, Wisconsin 53706, USA.
Oertel
Donata
D
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D000831:Animals, Newborn; D017626:Cochlear Nucleus / Q000166:cytology*; D004056:Differential Threshold / Q000502:physiology* / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004546:Elapid Venoms / Q000494:pharmacology; D004553:Electric Conductivity; D004558:Electric Stimulation / Q000379:methods; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D018408:Patch-Clamp Techniques / Q000379:methods; D011188:Potassium / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
D004546:Elapid Venoms; C020273:dendrotoxin; D011188:Potassium