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THE EFFECT OF INTRAVENOUS ADMINISTRATION OF GABA AND BRAIN EXTRACTS ON BLOOD PRESSURE IN THE RAT
Author(s) -
Horvath J. S.,
Baxter Claire R.,
Duggin G.,
Tiller D. J.
Publication year - 1980
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1980.tb00096.x
Subject(s) - propranolol , phentolamine , chemistry , blood pressure , pharmacology , blockade , sephadex , anesthesia , medicine , endocrinology , biochemistry , receptor , enzyme
SUMMARY 1. A rat bioassay was used to study pressor substances in brain extracts. 2. A compound with pressor activity in pentolinium‐treated rats was extracted from brain, purified using Dowex, Sephadex electrophoresis and identified as γ‐aminobutyric acid (GABA) by HPLC and mass spectrometry. 3. Intravenous GABA (1‐5 μg) or brain extracts caused a dose dependent decrease in blood pressure in pentobarbitone‐anaesthetized rats. 4. After ganglion blockade with pentolinium (2 mg/kg subcutaneously), GABA or brain extracts cause a dose dependent increase in rat blood pressure. 5. This pressor effect is reduced by α‐ and β‐blockers (intravenous phentol‐amine, 0‐5 mg/kg and propranolol, 005 mg/kg). 6. It is concluded that GABA causes a fall in blood pressure by a central mechanism and ganglion blockade unmasks a pressor effect.