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Involvement of endothelin in the pressor response following injection of NMDA to the periaqueductal gray area of rats
Author(s) -
D'Amico Michele,
Warner Timothy D.
Publication year - 1995
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.1476-5381.1995.tb15927.x
Subject(s) - nmda receptor , periaqueductal gray , microinjection , endocrinology , medicine , antagonist , receptor antagonist , angiotensin ii , chemistry , endothelin receptor , receptor , central nervous system , midbrain
Microinjection of N‐methyl‐D‐aspartate (NMDA) (0.068 to 6.8 nmol) into the periaqueductal gray area (PAG) of anaesthetized rats caused dose‐dependent increases in blood pressure. Preinjection (10 min before) of FR 139317 (an ET A receptor selective antagonist; 5 nmol) or SB 209670 (an ET a /ET b receptor non‐selective antagonist; 5 nmol) to the PAG reduced the pressor response to NMDA whereas BQ‐788 (an ET B receptor selective antagonist; 5 nmol) did not affect the NMDA‐induced hypertension. Pretreatment with DL‐2‐amino‐5‐phosphono valeric acid (2‐APV) (an NMDA receptor selective antagonist, 5 nmol) also abolished the pressor response induced by NMDA. Dose‐dependent increases in blood pressure induced by injection of angiotensin II (0.1–10 nmol) to the PAG were unaffected by FR 139317 or SB 209670. Thus, our data indicate that endogenous ET‐1, via an action on ET A receptors, contributes to the pressor effects of NMDA within the brain.