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ENHANCED SENSITIVITY OF MEDULLARY DEPRESSOR NEURONS TO N ‐METHYL‐ D ‐ASPARTATE–GLYCINE SITE ANTAGONISTS IN THE SPONTANEOUSLY HYPERTENSIVE RAT
Author(s) -
Kapoor Ranjna,
Kapoor Vimal
Publication year - 1998
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.1440-1681.1998.t01-6-.x
Subject(s) - kynurenic acid , nmda receptor , endocrinology , medicine , antagonist , microinjection , chemistry , glycine , inhibitory postsynaptic potential , amino acid , receptor , biochemistry
1. The effects of the specific N ‐methyl‐ D ‐aspartate (NMDA)–glycine site antagonist 5‐fluoro indole‐2‐carboxylic acid (FICA) and NMDA, microinjected into the vasodepressor caudal ventrolateral medulla, were compared in spontaneously hypertensive rats (SHR) and in Wistar‐Kyoto (WKY) rats. 2. 5‐Fluoro indole‐2‐carboxylic acid elicited a significant pressor response (+20.0±4.9 mmHg) in SHR, but no change was found in the basal blood pressure of WKY rats. 3. The depressor response due to NMDA microinjection was significantly larger in SHR (–48.0±4 mmHg) than in WKY rats (–23.0±1.9 mmHg). 4. Pre‐injection of FICA attenuated the depressor effects of NMDA significantly, this blockade being significantly more pronounced in SHR (37.0±2.7 mmHg) than in WKY rats (12.0± 1.2 mmHg). 5. The enhanced responses to FICA may reflect the lower levels of the endogenous NMDA–glycine antagonist kynurenic acid in SHR compared with WKY rats.