Co-Existence of Nitric Oxide Synthase Positive Neurons and Vasopressin in the Supraoptic Nucleus of the Spontaneously Hypertensive Rat

Objective: The co-existence of nitric oxide synthase(NOS) positive neurons and vasopressin was to be investigated in Supraoptie nucleus (SON) of Spontaneously hypertensive rat(SHR) and normal rat. Methods: The morphology and distribution of NOS positive neurons and AVP immunoreactive neurons were observed respectively in SON of both SHR and normal rat, and the co-existence of NOS with AVP was also observed by using NADPH-diaphorase histochemical technique combined with immunocytochemical methods in the same section. Results: The morphology and distribution of NOS positive neurons and AVP immunoreactive neurons were fundamentally similar in the SON, and the ratio of co-existence of NOS-AVP was very high. The percentage of NOS and AVP double -labeled neurons to total labeled neurons in SON of SHR hypothalamus was about 62. 7%. Doubled-labeled neurons were mainly located in the ventral part of the SON. And the percentage of NOS and AVP double-labeled neurons to total labeled neurons in SON of normal rat hypothalamus was about 72. 3%. Conclusion: These results suggest 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.