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SUBSTANCE P INCREASES HYPOTHALAMIC BLOOD FLOW VIA AN INDIRECT ADRENERGIC‐CHOLINERGIC INTERACTION
Author(s) -
KLUGMAN K.P.,
LEMBECK F.,
MARKOWITZ S.,
MITCHELL G.,
ROSENDORFF C.
Publication year - 1980
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.1476-5381.1980.tb10982.x
Subject(s) - phenoxybenzamine , propranolol , substance p , chemistry , atropine , blockade , cholinergic , endocrinology , medicine , adrenergic , acetylcholine , vasodilation , mecamylamine , tolazoline , pharmacology , antagonist , neuropeptide , receptor
1 Hypothalamic blood flow (HBF) was measured in conscious rabbits by the 133 xenon washout technique. 2 Substance P in a dose of 50 or 500 ng increases HBF while 5 ng is without effect. 3 Cholinoceptor blockade, with either atropine or mecamylamine abolishes the vasodilator effect of substance P. 4 Chemical sympathectomy of the hypothalamus with 6‐hydroxydopamine, or adrenoceptor blockade with either propranolol or phenoxybenzamine abolishes the effect of substance P on HBF. 5 Destruction of the intracerebral noradrenergic pathway (INP), or blockade of its vasodilator action, with barbiturate or bicarbonate, likewise prevent the vasodilator action of substance P. 6 These results suggest that substance P may cause an increase in HBF via the release of endogenous acetylcholine, which in turn stimulates the INP.