TY - JOUR
T1 - Antagonism by propranolol of the ganglion stimulant action of 5-hydroxytryptamine
AU - Weinstock, Marta
AU - Schechter, Yael
PY - 1975
Y1 - 1975
N2 - The effects of racemic propranolol and its constituent isomers were studied on ganglionic stimulation produced in situ by close arterial injection of 5-HT and DMPP to the superior cervical ganglion. Ganglion stimulation was recorded in terms of the resultant contraction of the nictitating membrane. d,l-Propranolol caused a biphasic antagonism of the ganglion stimulant effect of 5-HT. At low doses, 0.5-10 μg, the antagonism was surmountable by increasing the amount of 5-HT. The l-isomer (0.2-4 μg) but not d-propranolol also caused antagonism. At higher doses, 0.1-5 mg, both d,l- and d-propranolol caused a second type of blockade of 5-HT which was not surmountable and resembled that seen with procaine. The ganglion stimulatn effects of DMPP and acetylcholine were only antagonised by the higher doses of d- and d,l-propranolol. d,l-Propranolol did not reduce the direct stimulation by 5-HT on the muscle of the nictitating membrane.
AB - The effects of racemic propranolol and its constituent isomers were studied on ganglionic stimulation produced in situ by close arterial injection of 5-HT and DMPP to the superior cervical ganglion. Ganglion stimulation was recorded in terms of the resultant contraction of the nictitating membrane. d,l-Propranolol caused a biphasic antagonism of the ganglion stimulant effect of 5-HT. At low doses, 0.5-10 μg, the antagonism was surmountable by increasing the amount of 5-HT. The l-isomer (0.2-4 μg) but not d-propranolol also caused antagonism. At higher doses, 0.1-5 mg, both d,l- and d-propranolol caused a second type of blockade of 5-HT which was not surmountable and resembled that seen with procaine. The ganglion stimulatn effects of DMPP and acetylcholine were only antagonised by the higher doses of d- and d,l-propranolol. d,l-Propranolol did not reduce the direct stimulation by 5-HT on the muscle of the nictitating membrane.
KW - 5-HT
KW - d,l-Propranolol
KW - d-Propranolol
KW - DMPP
KW - Non-specific antagonism
KW - Specific antagonism
KW - Superior cervical ganglion
UR - http://www.scopus.com/inward/record.url?scp=0016592244&partnerID=8YFLogxK
U2 - 10.1016/0014-2999(75)90296-4
DO - 10.1016/0014-2999(75)90296-4
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C2 - 238859
AN - SCOPUS:0016592244
SN - 0014-2999
VL - 32
SP - 293
EP - 301
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
IS - 2
ER -