Abstract
A bimodal response to injected acetylcholine (ACh) occurred following pretreatment of the superior cervical ganglia of cats with either eserine or repetitive preganglionic stimulation. The "early" response was blocked by d-tubocurarine (dTC) but not by small doses of atropine. Conversely, the "late" response was sensitive to blockade by atropine but not large doses of dTC. Similarly, eserine, administered in relatively large doses, evoked a postganglionic discharge which was blocked by atropine but not dTC or mecamylamine (MCA). Furthermore, repetitive stimulation of ganglia treated with large doses of dTC produced an asynchronous postganglionic discharge which was sensitive to blockade by atropine.
These findings are consistent with the proposal that the asynchronous discharges induced by antiesterase agents or repetitive stimulation were due to ACh liberated from the nerve endings which, in turn, diffused across the synapse to act upon different cholinoceptive sites on time postsynaptic membranes of the ganglion cells.
Footnotes
- Received June 14, 1962.
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