To gain insight into the mechanisms underlying compensatory changes in excitability induced by thermal acclimation we examined the effects of short-term and long-term temperature transition on a transient outward potassium current (A-current) and the transient inward current in an identified neurone (Br) of the land snail Helix pomatia.
The A-current in neurones from snails acclimated to 20°C was suppressed by cooling to 3°C, with a Q10 of 4.5 between 10°C and 20°C. This is consistent with suppression of the ability of these neurones to fire repetitively at low temperatures.
Neurones acclimated to low temperature (5°C) partially recovered their ability to fire repetitively, but exhibited no A-current, at this temperature.
Neither the equilibrium potential for the A-current (EA), the steady-state inactivation parameters of the A-current (Bo), nor the ratio of the time constants of A-current activation and inactivation (τA/τB) were affected by cooling, leading to the conclusion that the reduction of the A-current by cooling was due to a decrease in the A-current activation parameters (GAA∞).
Cooling reduced the maximum peak inward current, with a Q10 of 2, in neurones from warm-acclimated animals. After acclimation to 5°C, maximum peak inward current partially recovered.
Cooling neurones from warm-acclimated animals slowed the time course of the recovery of inward current from inactivation. Acclimation to the cold caused a partial, compensatory shortening of the inactivation removal process.
Temperature Acclimation: Influence on Transient Outward and Inward Currents in an Identified Neurone of Helix Pomatia
- Views Icon Views
- Share Icon Share
- Search Site
DEJAN ZEČEVIĆ, HERBERT LEVITAN, MIRA PAŜIĆ; Temperature Acclimation: Influence on Transient Outward and Inward Currents in an Identified Neurone of Helix Pomatia. J Exp Biol 1 July 1985; 117 (1): 369–388. doi: https://doi.org/10.1242/jeb.117.1.369
Download citation file: