Central nitric oxide modulates hindquarter vasodilation elicited by AMPA receptor stimulation in the NTS of conscious rats
MetadataShow full item record
Microinjection of S-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) in the nucleus of the solitary tract (NTS) of conscious rats causes hypertension, bradycardia, and vasoconstriction in the renal, mesenteric, and hindquarter vascular beds. In the hindquarter, the initial vasoconstriction is followed by vasodilation with AMPA doses >5 pmol/100 nl. To test the hypothesis that this vasodilation is caused by activation of a nitroxidergic pathway in the NTS, we examined the effect of pretreatment with the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 10 nmol/100 nl, microinjected into the NTS) on changes in mean arterial pressure, heart rate, and regional vascular conductance (VC) induced by microinjection of AMPA (10 pmol/100 nl in the NTS) in conscious rats. AMPA increased hindquarter VC by 18 ± 4%, but after pretreatment with L-NAME, AMPA reduced hindquarter VC by 16 ± 7% and 17 ± 9% (5 and 15 min after pretreatment, P < 0.05 compared with before pretreatment). Pretreatment with L-NAME reduced AMPA-induced bradycardia from 122 ± 40 to 92 ± 32 beats/min but did not alter the hypertension induced by AMPA (35 ± 5 mmHg before pretreatment, 43 ± 6 mmHg after pretreatment). Control injections with D-NAME did not affect resting values or the response to AMPA. The present study shows that stimulation of AMPA receptors in the NTS activates both vasodilatatory and vasoconstrictor mechanisms and that the vasodilatatory mechanism depends on production of nitric oxide in the NTS. Copyright © 2006 the American Physiological Society.
How to cite this document
Showing items related by title, author, creator and subject.
Marçal, Anderson C.; Leonelli, Mauro; Fiamoncini, Jarlei; Deschamps, Francisco C.; Rodrigues, Maria A.M. ; Curi, Rui; Carpinelli, Angelo R.; Britto, Luiz R.G.; Carvalho, Carla R.O. (Cell Biochemistry and Function, 2013) [Artigo]Retinopathy, a common complication of diabetes, is characterized by an unbalanced production of nitric oxide (NO), a process regulated by nitric oxide synthase (NOS). We hypothesized that retinopathy might stem from changes ...
Myenteric denervation in gastric carcinogenesis: Differential modulation of nitric oxide and annexin-A1 Polli-Lopes, Ana Cláudia; Estofolete, Cássia F.; Oliani, Sonia M. ; Zucoloto, Sérgio; Cunha, Fernando Q.; Gil, Cristiane D. (International Journal of Clinical and Experimental Pathology, 2013) [Artigo]This study evaluated the properties of endogenous nitric oxide synthases (NOS) and annexin-A1 (ANXA1) and determined how they can be exploited in the N-methyl-N-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis ...
Tumitan, Ana Rita Paladino ; Monnazzi, Luis Gustavo Silva ; Ghiraldi, Fabrício Rodrigues ; Cilli, Eduardo Maffud ; De Medeiros, Beatriz Maria Machado (Microbiology and Immunology, 2007) [Artigo]Th1 cells, in cooperation with activated macrophages, are required to overcome Yersinia enterocolitica infection in mice. The pathway macrophages utilize to metabolize arginine can alter the outcome of inflammation in ...