HEAT-GENERATION ASSOCIATED WITH SYNAPTIC TRANSMISSION IN THE MAMMALIAN SUPERIOR CERVICAL-GANGLION

By use of a thermal detector constructed with a thin polyvinylidene fluoride film (PVDF), heat production in the superior cervical ganglion (SCG) of the guinea pig was examined. A single electric shock applied to the preganglionic nerve evokes a temperature rise of approximately 1.5 × 10−6 deg. The thermal responses summate when the preganglionic nerve is stimulated repetitively. The amplitude of the thermal response is increased when the preparation is treated with a high Ca2+ medium. Treatment with agents that block ganglionic transmission (high Mg2+, d‐tubocurarine, hexamethonium, TTX) reversibly suppresses thermal response. It is thus concluded that the thermal responses described in this paper are generated by the physio‐chemical events underlying postsynaptic electrogenesis in the SCG cells. Copyright © 1990 Wiley‐Liss, Inc.