The Effects of Bretylium and Guanethidine on Catecholaminergic Transmission in an Invertebrate
Year: 1974
Type: article
Abstract: 1 Secretory potentials produced by stimulation of the salivary duct nerves were recorded intracellularly from cockroach isolated salivary glands. The secretory potential normally consisted of a 40-80 mV hyperpolarization of the gland cell.2 Bretylium (0.1-1 mM) reduced the amplitude of the secretory potential without affecting the response of the gland to dopamine (0.25-1 muM). In addition, bretylium caused an increase in the frequency of miniature secretory potentials and the appearance of nerve terminal action potentials.3 Guanethidine (1 mM) reduced the response to nerve stimulation without depressing the sensitivity of the salivary gland to dopamine (0.25-0.5 muM) and without causing an increase in the occurrence of miniature potentials. Higher concentrations (4-5 mM) completely eliminated secretory potentials but also reduced the sensitivity of the gland cell to dopamine.5 These results indicate a presynaptic depression of the secretory potential by both bretylium and guanethidine. It is suggested that, in this system, bretylium acts by depolarizing the nerve terminal while guanethidine does not.
Source: British Journal of Pharmacology
Author: E.M. SILINSKY
Institution: University of Edinburgh
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2070482208