(960.2) Neuronal Nitric Oxide Synthase expression in brain from male spontaneously hypertensive rats. Implication in the control of cardiovascular function

Poster Board Number: E619

Grecia Peñaloza (Instituto de Fisiología, Universidad Autonoma de Puebla), Ernesto Cortes Gallardo (Instituto de Fisiología, Universidad Autonoma de Puebla), Ana Bocanegra Alfaro (Instituto de Fisiología, Universidad Autonoma de Puebla), Ma de Jesus Gómez (Instituto de Fisiología, Universidad Autonoma de Puebla)

Neuronal nitric oxide synthase (nNOS) in brain has been implicated in the regulation of sympathetic tone and control of cardiovascular functions, then in this study it was determined the nNOS expression and nitrites levels in brain from spontaneously hypertensive rats (SHR). Male Wistar Kyoto (WKY) and (SHR) strains at 4 months old were used, half of the experimental animals were administered with reserpine (R), (1 mg/kg of weight, for two weeks) and the others received vehicle (V) administration (dimethyl sulfoxide). Four experimental groups (WK+V, WKY+R, SH+V, SH+R) were followed and after cardiovascular parameters determination, brain was obtained. The expression of nNOS through western blot in frontal cortex-FC, occipital cortex-OC, cerebellum-CB, medulla oblongata-MO, spinal cord-EC was determined and nitrites levels in tissue homogenate from the same brain regions were measured through Griess reaction. Heart rate (HR), systolic arterial blood pressure (SABP) and body weight, were analyzed. The results show that reserpine decrease significantly the body weight in g (WK+V 335.2±17.6 versus WK+R 280.4±9.87; SH+V 334.8±9.01 versus SH+R 269.3±8.65), the HR in beat/min (WK+V 302.2±11.6 versus WK+R 264±9.13; SH+V 354±17 versus SH+R 224±16),  SABP in mmHg (WK+V: 165.8±4,964, versus WK+R 118.2±7.52; SH+V 215.4±5,074 versus SH+R 139.6±3.75), in both WKY and SHR (Plt;0.05 for all parameters). nNOS protein expression was high in WK+V in comparison with the SH+V, in FC and CB, whereas in the groups with reserpine administration the nNOS expression was higher in SH+R versus SH+V in FC, CB and MO. Tissue nitrites levels from different regions of the brain were reduced significantly in the SHR in comparison with WKY, particularly in FC (WK+V-5.11 ±0.60 versus SH+V 3.53±0.53) and MO (WK+V 7.84±0.84 versus SH+V 3.24±0.48), however in the groups SHR+R a significantly increased of nitrites levels was observed in comparison with their own control, particularly in CB (SH+V 3.91±1.04 versus SH+R 7.53±0.83) and MO (SH+V 3.72±0.44 versus SH+R 5.8±0.39) (Plt;0.05 for all parameters). Increased nNOS expression in frontal cortex and cerebellum produces a significant decrease in the heart rate and systemic arterial blood pressure suggesting a key role of nNOS in the regulation of cardiovascular function in the SHR.

Support or Funding Information

Funding: This work was supported by grants from Vicerrectoria de Investigación y Posgrado-Benemérita Universidad Autónoma de Puebla (2020-2021)

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Funding: This work was supported by grants from Vicerrectoria de Investigaciamp;oacute;n y Posgrado-Benemamp;eacute;rita Universidad Autamp;oacute;noma de Puebla (2020-2021)lt;/pgt;