the effect of nucleus tractus solitarius nitric oxidergic neurons on blood pressure in diabetic rats

it has been shown that nitric oxide is synthesized in the central nervous system as well as in vascular endothelial cells. recently, it was reported that nitric oxide was involved in central cardiovascular regulation, baroreflex modulation, and involved in a reciprocal release with excitatory amino acids in the nucleus tractus solitarii of rats. the purpose of the present study was to investigate the possible interaction of nitric oxide and glucose in the nucleus tractus solitarii on blood pressure regulation. male wistar stereptozotocin induced diabetic rats were anesthetized with urethane. a cannula was inserted above the nucleus tractus solitarii and blood pressure was monitored intra-arterially. unilateral microinjection of l-glutamate (2.3 nmol/60 nl) into the nucleus produced a decrease in blood pressure in diabetic rats. microinjection of lidocaine (0.5 µl %2) increased blood pressure. unilateral microinjection of sodium nitroprusside (100 mmol/60 nl) into the nucleus increased blood pressure in diabetic rats. after microinjection of sodium nitroprusside, the depressive responses to glutamate were significantly attenuated. these results demonstrated the probable role of glucose on blood pressure regulation in diabetic animals affecting on nitric oxidergic neurons and so it implicates an interaction between nitric oxide and glucose in central cardiovascular regulation. iran. biomed. j. 10 (1): 15-19, 2006