[Role of substance P in pressor response of lateral hypothamus-perifornical region to glutamate].
Substance P(SP)-immunoreactive cell bodies, axon terminals and SP receptors were widely scattered in most pressor areas. Lateral hypothalamus (LH) contains SPergic neurons; and SPergic fibers-SP receptors are present in LH projection areas; hence the role of SP in LH-pressor response was studied. The results showed that: (1) microinjection of glutamate into the lateral hypothalamus-perifornical region (LH/PF) or SP into LH projection areas: the locus coeruleus (LC), periaqueductal gray matter (PAG) or nucleus parabrachialis (NPB), respectively, all could induce pressor response; (2) preinjection of DPDPDT (a substance P antagonist) into the LC, PAG (but not NPB) reduced the LH/PF pressor response; (3) intra-RVL (rostral ventrolateral medulla) injection of phentolamine, propranolol or atropine also markedly attenuated the LH/PF pressor response. Taken together with our previous findings that alpha-, beta- and M-receptors in the RVL mediated the pressor response to excitation of LC, and alpha-, beta-receptors mediated the PAG-pressor response, it is suggested that the LH/PF pressor response may be brought about via the activation of LC- and PAG-RVL systems by SPergic fibers from the LH/PF.
D000818:Animals; D001794:Blood Pressure; D018698:Glutamic Acid / Q000494:pharmacology*; D007031:Hypothalamus / Q000502:physiology*; D008125:Locus Coeruleus / Q000502:physiology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology; D008845:Microinjections; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000494:pharmacology / Q000502:physiology*