P物质在谷氨酸兴奋外侧下丘脑—穹窿周围区引起的升压反…

Ｐ物质（ＳＰ）能神经元及其轴突末和受体广泛分布于很多心血管中枢。外侧下丘脑含ＳＰ能神经元，外侧下丘脑投射的升压区内又存在ＳＰ能纤维及ＳＰ受体；因此本工作检验ＳＰ在外侧下丘脑升压反应中的作用。实验显示：（１）Ｌ－谷氨酸兴奋外侧下天脑的穹窿周围区（ＬＨ／ＰＦ）或将ＳＰ分别注入各ＬＨ投射区，蓝斑（ＬＣ）、臂旁核（ＮＰＢ）或 导不管周围灰质（ＰＡＧ）均引起升压反应；（２）「Ｄ－Ｐｒｏ＾２，Ｄ－Ｐｈｅ＾７，

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.