Premium
Increased Renal Pelvic Pressure Elicits Excitatory or Inhibitory Responses in Rat Renal Afferent Nerves that is Reduced by Renal Nerve Ablation
Author(s) -
Janks Laura,
Knuepfer Mark
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.830.8
Subject(s) - excitatory postsynaptic potential , inhibitory postsynaptic potential , denervation , ablation , medicine , anesthesia , anatomy , endocrinology , chemistry
Renal denervation by radiofrequency (RF) ablation has been reported to ameliorate resistant hypertension and other cardiovascular diseases. Many have suggested that afferent renal nerves (ARN) are responsible for this effect. We hypothesized that mechanoreceptors in ARN have both excitatory and inhibitory properties that can be prevented by RF ablation. Rats underwent sham or RF ablation of renal nerves using an external electrode designed to fit around the renal artery. After 4, 20 or 52 weeks, rats were anesthetized with 1.5% isoflurane in order to test ARN. After left renal pelvic cannulation through the ureter, ARN activity was recorded from the renal nerve after decentralization. In control rats, increases in renal pelvic pressure (12±1 and 22±1 mmHg for 45 s) elicited one of two patterns of activity. In the majority of nerve bundles, there was an initial (within 5 s) rapidly adapting excitatory ARN response (32±4%) followed by a smaller sustained increase (12±4%) in ARN activity (N=13). A smaller number of nerve bundles displayed an initial (‐6±2%) and sustained (‐9±5%) inhibitory responses (n=5). RF ablation significantly attenuated ARN responses although small excitatory or inhibitory responses were still observed. These data suggest that both excitatory and inhibitory mechanoreceptor afferents exist in ARN and that different nerve bundles carry different proportions of these excitatory and inhibitory fibers. Our data, and that of others, suggest that excitatory mechanoreceptors predominate. RF ablation was successful in producing a long‐lasting denervation of these nerves. The role of these excitatory and inhibitory mechanoreceptors is not understood. Supported by St. Louis University.