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Effect of amphetamine on the transmission of repetitive impulses through the isolated superior cervical ganglion of the rat
Author(s) -
DOWNING O. A.
Publication year - 1972
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.1476-5381.1972.tb07239.x
Subject(s) - amphetamine , phenoxybenzamine , superior cervical ganglion , reserpine , stimulation , medicine , endocrinology , chemistry , ganglion , excitatory postsynaptic potential , isoprenaline , carbachol , propranolol , anesthesia , dopamine , anatomy , inhibitory postsynaptic potential
Summary1 The cervical sympathetic trunk of the isolated rat superior cervical ganglion was stimulated with short bursts of repetitive pulses. At room temperature with rates of stimulation of 4 Hz and above, the ganglionic action potentials were reduced in size. 2 Amphetamine (2·7 × 10 −5 m ), which caused some depression of transmission during stimulation at 0·1 Hz, caused a partial reversal of the depression of transmission occurring with rates of stimulation above 4 Hz. 3 This action of amphetamine was mimicked by adrenaline (3 × 10 −5 m ) and noradrenaline (9·6 × 10 −5 m ) but not by isoprenaline (1·8 × 10 −5 m ) and was unaffected by propranolol (1·4 × 10 −5 m ) but was abolished by prior application of phenoxybenzamine (5·8 × 10 −6 m ). Furthermore, this action of amphetamine was unaltered in ganglia taken from rats pretreated with reserpine (single dose of 6 mg/kg, 16 h before dissection). 4 Amphetamine had no effect on the surface potentials of the ganglion or on changes in these potentials produced by concentrations of carbachol (5·5 × 10 −6 m to 5·5 × 10 −3 m ). 5 It is concluded that amphetamine has a direct action on α‐adrenoceptors situated at presynaptic sites.