Altered responsiveness of medullary depressor neurones to L-glutamate and D-serine in SHR rats.
We have investigated the effects of microinjection of L-glutamate, D-serine and glycine into the caudal ventrolateral medulla (CVLM) of spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. In SHR the depressor responses to L-glutamate were significantly enhanced compared to WKY rats, while those to the NMDA-glycine site agonists, D-serine and glycine (in the presence of strychnine) were significantly diminished. Depressor responses to NMDA and D-serine could be blocked with 5-fluro-indole-2-carboxylic acid (FICA, an NMDA-glycine site antagonist). In support of our previous findings, the larger responses of NMDA-glutamate site agonists and smaller responses of NMDA-glycine site agonists in SHR, may suggest that SHR have reduced levels of the endogenous glutamate antagonist, kynurenic acid.
Kapoor
V
V
Department of Molecular Sciences, James Cook University, Townsville, Australia.
Kapoor
R
R
Chalmers
J P
JP
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D007736:Kynurenic Acid / Q000378:metabolism; D008526:Medulla Oblongata / Q000166:cytology / Q000187:drug effects*; D008845:Microinjections; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D018009:Receptors, Glycine / Q000819:agonists*; D012694:Serine / Q000494:pharmacology*; D013237:Stereoisomerism
D018009:Receptors, Glycine; D018698:Glutamic Acid; D012694:Serine; D007736:Kynurenic Acid