Carotid Body Artery Removal (CBX) Prevents Training‐Induced Plasticity in the preautonomic Vasopressinergic (VPergic) Neurons of the Paraventricular Nucleus

Abstract

We observed that sinoaortic denervation prevents T-induces plasticity in the VPergic preautonomic PVN cells (Cavalleri et al., FASEB J. 2, 607.2). In the present study, we sought to investigate whether peripheral chemoreceptors mediate VPergic plasticity in PVN subnuclei. Rats CBX or SHAM were trained (for 3 month) or kept sedentary (S). After cardiovascular records, rats were anesthetized and perfused (PFA 4%). Immunorreactivity (ir) was performed, using VP first antibody (1:20.000). CBX abolished pressor and bradicardic responses to chemoreflex activation (KCN 40 μg, iv) in S and T rats but not changes in the baroreflex function. T-induced increase in the Vasopressin (VP)-ir (ShamS vs. ShamT) in the dorsal cap [DC (11 ± 1 vs 20 ± 1 % density)] and ventro-medial [VM (14 ± 1 vs 54 ± 3)] but not in the magnocellular [Mg (41 ± 5 vs 34 ± 3 % density)] subnucleus. CBX induces a decrease in the VP-ir (ShamS vs. CBXS) in the Mg (41 ± 4 vs 11 ± 1 % density) and DC (11 ± 1 vs 5 ± 1 % density), but not in the VM (14 ± 1 vs 17 ± 1) subnucleus. CBX abolish T-induces VP plasticity (CBXS vs. CBXT) in the VM [17 ± 1 vs 21 ± 4 % density] but not in the Mg (5 ± 1 vs 12 ± 1 % density)] or DC (11 ± 1 vs 58 ± 10 % density)] subnuclei. Chemoreflex afferent are important for the basal synthesis of VP cells in the different PVN subnuclei; on the other hand, T. was effect to correct CBX induced changes only in the DC preautonomic subnucleus. Financial Support: CNPq, FAPESP.