Premium
THE EFFECTS OF BRETYLIUM AND GUANETHIDINE ON CATECHOLAMINERGIC TRANSMISSION IN AN INVERTEBRATE
Author(s) -
SILINSKY E.M.
Publication year - 1974
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1974.tb10671.x
Subject(s) - bretylium , guanethidine , medicine , endocrinology , stimulation , catecholaminergic , dopamine , depolarization , chemistry , salivary gland , biology , adrenergic , receptor
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 M m ) reduced the amplitude of the secretory potential without affecting the response of the gland to dopamine (0.25–1 μ m ). In addition, bretylium caused an increase in the frequency of miniature secretory potentials and the appearance of nerve terminal action potentials. 3 Guanethidine (1 M m ) reduced the response to nerve stimulation without depressing the sensitivity of the salivary gland to dopamine (0.25–0.5 μ m ) and without causing an increase in the occurrence of miniature potentials. Higher concentrations (4–5 M m ) 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.