Macrophage-dependent impairment of α2-adrenergic autoreceptor function in sympathetic neurons from DOCA-salt but not high fat diet-induced hypertensive rats.

Macrophage-dependent impairment of α2-adrenergic autoreceptor function in sympathetic neurons from DOCA-salt but not high fat diet-induced hypertensive rats. Am J Physiol Heart Circ Physiol. 2018 Jan 05;: Authors: Mui RK, Fernandes R, Garver H, van Rooijen N, Galligan JJ Abstract DOCA-salt and obesity-related hypertension are associated with inflammation and sympathetic nervous system hyperactivity. Prejunctional α2-adrenergic receptors (α2ARs) provide negative feedback to norepinephrine release from sympathetic nerves through inhibition of N-type Ca2+ channels. Increased neuronal norepinephrine release in DOCA-salt and obesity-related hypertension occurs through impaired α2AR signaling, however, the mechanisms involved are unclear. Mesenteric arteries are resistance arteries that receive sympathetic innervation from the superior mesenteric and celiac ganglia (SMCG). We tested the hypothesis that macrophages impair α2AR-mediated inhibition of Ca2+ channels in SMCG neurons obtained from DOCA-salt and high fat diet (HFD)-induced hypertensive rats. Whole cell patch clamp methods were used to record Ca2+ currents from SMCG neurons maintained in primary culture. We found that DOCA-salt but not HFD-induced hypertension caused macrophage accumulation in mesenteric arteries, increased SMCG mRNA levels of monocyte chemoattractant protein-1 and tumor necrosis factor-α, and impaired α2AR-mediated inhibition of Ca2+ currents in SMCG neuro...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research