State-dependent modulation of sympathetic firing by α1-adrenoceptors requires constitutive PKC activity in the neonatal rat spinal cord.

State-dependent modulation of sympathetic firing by α1-adrenoceptors requires constitutive PKC activity in the neonatal rat spinal cord. Auton Neurosci. 2020 May 23;227:102688 Authors: Su CK Abstract The central adrenergic and noradrenergic neurotransmitter systems diffusively affect the operation of the spinal neural network and dynamically gauge central sympathetic outflow. Using in vitro splanchnic nerve-thoracic spinal cord preparations as an experimental model, this study examined the intraspinal α1-adrenoceptor-meidated modulation of sympathetic firing behaviors. Several sympathetic single-fiber activities were simultaneously recorded. Application of phenylephrine (Phe, an α1-adrenoceptor agonist) increased, decreased or did not affect spontaneous firing. A log-log plot of the change ratios of the average firing rates (AFR) versus their basal AFR displays a linear data distribution. Thus, the heterogeneity in α1-adrenoceptor-mediated responses is well described by a power law function. Phe-induced power-law firing modulation (plFM) was sensitive to prazosin (Prz, an α1-adrenoceptor antagonist). Heparin (Hep, a competitive IP3 receptor blocker) and chelerythrine (Che, a protein kinase C inhibitor) also caused plFM. Phe-induced plFM persisted in the presence of Hep; however, it was occluded by Che pretreatment. Pair-wise analysis of single-fiber activities revealed synchronous sympathetic discharges. Application of Phe, Hep ...
Source: Autonomic Neuroscience - Category: Neuroscience Authors: Tags: Auton Neurosci Source Type: research