Neuronal nitric oxide synthase in the rostral ventrolateral medulla of hindlimb unloaded rats

Abstract

Prolonged periods of bed rest or spaceflight result in cardiovascular deconditioning and a predisposition for orthostatic intolerance. Hindlimb unloaded (HU) rats are an animal model of deconditioning and exhibit blunted baroreflex sympathoexcitation. The rostral ventrolateral medulla (RVLM) is important for maintaining arterial pressure and baroreflex function. GABAergic inhibition in the RVLM is increased in HU rats. Nitric oxide (NO) is an important neuromodulator shown to increase GABA inhibition and may contribute to the enhanced GABAergic inhibition in the RVLM following HU. We hypothesized that 14 days of HU increases neuronal NO synthase (nNOS) in the RVLM. The unilateral distributio..