Increase in cell size underlies neuron-specific temperature acclimation in Aplysia.
Aplysia californica with similar genetic and environmental backgrounds were raised under mariculture conditions at either 10 or 20 degrees C. Determinations of cell surface area using capacitance and visual measurements indicated that there was an increase in the surface area of identified neurons. However, this increase was cell specific, occurring only in certain identified neurons. The amplitude of the early potassium current (IA) was monitored in identified neurons from the cold- and warm-reared groups during acute changes in temperature. The response to acute temperature change differed in the two groups, indicative of partial temperature acclimation of IA. Cold rearing shifted the acute temperature-response curve for IA amplitude to color temperatures, compared with the temperature-response curve for animals reared at warmer temperatures. This acclimation was related to the increase in surface area previously noted. Cells showing an increase in IA amplitude in cold-reared animals also showed an increase in membrane surface area, presumably associated with an increased number of A-channels, while channel density was unchanged. There was a small but significant shift in the steady-stage voltage dependency of inactivation, whereas kinetic properties were unaffected by rearing temperature.
Treistman
S N
SN
Department of Pharmacology, University of Massachusetts Medical Center, Worcester 01655.
Grant
A J
AJ
D000064:Acclimatization; D000818:Animals; D001048:Aplysia / Q000502:physiology*; D005724:Ganglia / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D012044:Regression Analysis; D013696:Temperature
D007473:Ion Channels