[Pressor response induced by glutamate injection into caudal ventrolateral part of periaqueductal gray matter and its efferent pathway in brain-stem].
In urethane-anesthetized, tubocurarine-immobilized artificially ventilated rats, the following results were observed: (1) Sodium glutamate (Glu) microinjection into the caudal ventrolateral part of the periaqueductal gray matter (PAG) produced a marked rise in blood pressure. (2) This effect was attenuated by phentolamine or propranolol but not by atropine, injected bilaterally into the rostral ventrolateral medulla (RVL), indicating that this pressor response is mediated by RVL and alpha- and beta-receptors. (3) Propranolol-injection into RVL also attenuated the pressor response induced by electrical stimulation of the nucleus parabrachialis ventralis (NPV), while the pressor response initiated by injecting Glu into the same area (NPV) was not affected. Taken together with the previous findings that phentolamine blocks the pressor response produced by NPV-electrostimulation, but not of Glu-injection into NPV, the above results suggest that neurons in the caudal ventrolateral part of PAG may either send axons passing through the nucleus parabrachialis (NPB) and directly acting upon beta-receptors in RVL, or relay in NPB and act indirectly on alpha-receptors in RVL to produce the pressor response.
Chu
Z G
ZG
Feng
J
J
Ku
Y H
YH
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001933:Brain Stem / Q000502:physiology*; D004525:Efferent Pathways; D005971:Glutamates / Q000494:pharmacology*; D008297:Male; D008845:Microinjections; D010487:Periaqueductal Gray / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012970:Sodium Glutamate / Q000494:pharmacology*
D005971:Glutamates; D012970:Sodium Glutamate