Electroreceptor mechanisms of the ampullae of lorenzini in skates

Autor: G. R. Broun, V. I. Govardovskii
Rok vydání: 1983
Předmět:
Zdroj: Neurophysiology. 15:139-146
ISSN: 1573-9007
0090-2977
DOI: 10.1007/bf01060125
Popis: Responses of the receptor epithelium of single electrically isolated ampullae of Lorenzini and spike responses of nerve fibers connected to them to electrical stimulation under voltage clamping conditions were studied in experiments on the Black Sea skateRaja clavata. The preparations had an input resistance of 200–800 KΩ, a transepithelial resting potential of between 0 and −2 mV, and the usual spontaneous spike activity in their afferent fibers. Thresholds of the electroreceptors were 2–10 µV (current about 10−11 A). Within the working range of the electroreceptors (up to ±500 µV, current up to 1 nA) the current-voltage characteristic curve of the epithelium was linear without any evidence of spike or wave activity of the receptor cells. With negative currents of over 1–10 nA a regenerative spike appeared on the epithelium and was accompanied by an uncharacteristic pattern of spike discharge of the nerve fiber. It is concluded that, contrary to Bennett's hypothesis, spike or oscillatory activity bears no relationship to normal working of electroreceptors. It is postulated that "secondarily sensitive" receptor cells share a common functional organization, which is based on a chemical synapse with high electrical sensitivity.
Databáze: OpenAIRE
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