Capsaicin-sensitive adrenal sensory fibers participate in compensatory adrenal growth in rats.
Compensatory adrenal growth, in which one gland undergoes hyperplasia after removal of the other, is mediated by a neural reflex. In the present studies, a method employing capsaicin to selectively remove adrenal sensory fibers was developed and applied to determine whether adrenal capsaicin-sensitive fibers participate in compensatory adrenal growth. The splanchnic nerves of anesthetized male rats were treated with capsaicin or vehicle. Capsaicin treatment selectively removed adrenal calcitonin gene-related peptide-positive fibers. One week after drug treatment, rats underwent left adrenalectomy or sham surgery and recovered for 5 days. Capsaicin treatment bilaterally or to the left splanchnic nerve alone (i.e., the afferent nerve in the reflex) impaired compensatory adrenal growth at 5 days compared with vehicle controls, whereas capsaicin treatment to the right splanchnic nerve alone did not affect growth. Moreover, left adrenalectomy induced c-Fos immunolabeling in ipsilateral dorsal spinal cord that was prevented by capsaicin treatment. These data suggest that adrenal capsaicin-sensitive afferent nerves participate in compensatory adrenal growth and that this effect is primarily on the afferent limb of the reflex.
Ulrich-Lai
Yvonne M
YM
Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Marek
Daniel J
DJ
Engeland
William C
WC
D000222:Adaptation, Physiological / Q000187:drug effects; D000311:Adrenal Glands / Q000254:growth & development* / Q000294:innervation*; D000315:Adrenalectomy; D000818:Animals; D001369:Axons / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology*; D007839:Functional Laterality; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects* / Q000502:physiology*; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology; D013116:Spinal Cord / Q000378:metabolism; D013153:Splanchnic Nerves / Q000187:drug effects
D016760:Proto-Oncogene Proteins c-fos; D002211:Capsaicin