Substance P analogues potentiate the pressor response to microinjection of L-glutamate into laminas I and II of the cat dorsal horn.
Microinjection of a substance P analogue (1 mM; 7 or 10 nl) into laminae I and II of the L7 dorsal horn of decerebrate cats significantly potentiated (P < 0.05) the increase in arterial pressure evoked by microinjection of L-glutamate (109 mM; 7 or 10 nl) into these spinal sites. Microinjection of the substance P analogues (i.e., GR73638 and [Sar9,Met(O2)11]-substance P) which were selective NK-1 receptor agonists, had no impact on the cardioacceleration evoked by microinjection of L-glutamate (P > 0.05). In addition, microinjection of these analogues had no effect on the modest and non-significant increase in phrenic nerve discharge evoked by L-glutamate. We conclude that stimulation of NK-1 receptors in the superficial laminae of the dorsal horn potentiates the pressor responses to microinjection of L-glutamate.
Beyaert
C A
CA
Department of Internal Medicine, University of California, Davis, 95616, USA.
Hill
J M
JM
Kaufman
M P
MP
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D002909:Chronobiology Phenomena / Q000187:drug effects; D004357:Drug Synergism; D018698:Glutamic Acid / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D008845:Microinjections; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology*
C062618:substance P, Sar(9)-Met(O2)(11)-; D013373:Substance P; D018698:Glutamic Acid