DIFFERENT FORMS OF AFFERENT NERVE INPUT IN CARDIAC AND RENAL DISEASE IN RATS?. (April 2021)

• Record Type: Journal Article
• Authors: Rodionova, Kristina; Ditting, Tilmann; Pickny, Lisa; Ott, Christian; Schmieder, Roland; Schiffer, Mario; Amann, Kerstin; Veelken, Roland
• Is Part Of: Journal of hypertension. Volume 39(2021)e-Supplement 1
• Publication Date: 2021-04
• Subjects: Hypertension -- Periodicals; Hypertension -- Periodicals; 616.132005
• DOI: 10.1097/01.hjh.0000747284.82066.e1
• Languages: English
• ISSNs: 1473-5598

Abstract

Abstract : Objective: Afferent nerve pathways form kidney and heart are said to control sympathetic renal nerve activity. In a renal disease model the responsiveness of afferent renal nerve units was shifted from units with highly active primary neurons (tonic response pattern) to units with neurons of very low activity upon stimulation (phasic response pattern). Afferent renal nerve activity was likely decreased. Likewise, afferent vagal nerve activity in congestive heart failure (CHF) had a lower frequency at saturation than controls. Hence we wanted to test the hypothesis that CHF the vagal afferent nerve pathway consists of a decreased number of highly active tonic sensory neurons in the nodose ganglion. Design and method: CHF was induced by coronary artery ligature, nephropathy by injections of an anti Thy1.1 antibody (OX7, 1.2 mg/kg). After a respective time (CHF 21 days, nephropathy 7 days after induction) nodose ganglion neurons with cardiac vagal afferents from CHF rats or neurons form dorsal root ganglia with renal afferents from rats with nephropathy were cultured. Current clamp was used to characterize neurons as tonic, i.e. sustained action potential (AP) firing or phasict, i.e. <5 APs upon current injection.. More than 100 neurons were investigated. Results: In CHF rats, the number of neurons with a tonic response pattern did not differ from controls (64% vs. 70 %, ns). However, tonic cardiac neurons from CHF rats exhibited an increased production of action potentials compared (24.4+/-5.0 vs. 14.7+/-1.8 APs/10 s; p < 0.05; mean+/-SEM). In nephropathic rats, the number of neurons with a tonic response pattern decreased significantly (43% vs. 64 %, p < 0.05), but there was no difference in action potential production between groups. Conclusions: In congestive heart failure the number of afferent neurons with a tonic response pattern was not significantly altered. However, the action potential production of these neurons even significantly increased upon stimulation. Hence, in congestive heart failure vagal afferent neurons increase their sensitivity in the presence of impaired intracardiac receptors whereas in renal disease the responsiveness of the first part of the afferent pathway is impaired as a whole.