Distribition And Coexistence Of Nitric Oxide Synthase (NOS) Positive Neurons With Arginine Vasopressin (AVP) In Supraoptic Nucleus (SON),Paraventricular Nucleus (PVN) And Cerebrospinal Fluid-contacting Neurons (CSFCN) Of The Third Ventricle (3V) In

Objective: The coexistence of nitric oxide synthase(NOS) positive neurons with vasopressin was investigated in the supraoptic nucleus(SON) , paraventricular nucleus (PVN) and cerebrospinal fluid-contacting neurons(CSFCN) of the third ventricle(3V) in the spontaneously hypertensive rat(SHR) and the normal rat. Methods: The morphology and distribution of NOS positive neurons and AVP immunoreactive neurons were observed respectively in SON , PVN and CSFCN of 3V in both SHR and the normal rat, and the coexistence of NOS with AVP was also observed by using NADPH-diaphorase histochemical technique combined with immunocytochemical methods in the same section. Results: 1 .The morphology and distribution of NOS positive neurons and AVP immuno-positive neurons were fundamental similarity in SON and PVN.The number of NOS positive neurons of SHR was much less than that of SD, but the number of AVP immuno-positive neurons of SHR was more than that of SD. There was no significant difference between SHR and SD in PVN. The ratio of coexistence in the SON of the normal rat was higher than that of SHR. And in the different part of PVN, the coexistence of NOS with AVP was found also,with the highest degree of NOS-AVP coexistence in PVL. But there was also no significant difference between two group of rats. 2.The proportion of AVP in SON and PVN of SHR was significant higher than that of SD ,and theproportion of NOS in the two nuclei neurons of SD was higher than that of SHR. 3. There were a large number of NOS-AVP double -labeled CSFCN in the region of 3V of SHR.Conclusion: The ratios of such coexistence varied in SON , PVN and CSFCN of 3V of both SHR and the normal rat ,which suggested that NO and AVP may play an important role in modulating blood pressure of the hypothalamic neuroendocrine regulations ,and may be related to the occurrence and development of hypertension. NOS-CSFCN and NOS/AVP-CSFCN in the region of 3V in the SHR might modulate blood pressure by hypothalamus-cerebrospinal fluid-hypophysis neuroendocrine regulation.