Control of postganglionic sympathetic efferent fibers by neurokinin 1 receptors in rats.
Substance P (SP) is released peripherally from nociceptive terminals and has a direct effect on vascular cells. The present study suggests an indirect effect as well. In normal rats and rats with one hindpaw inflamed for 48 h following intraplantar injection of complete Freund's adjuvant, neurokinin 1 (NK1) receptors were immunohistochemically localized on postganglionic sympathetic axons. The percentage of NK1-labeled axons in the gray rami from normal rats was 35.0+/-5.0; in inflamed rats this percentage increased significantly to 49.1+/-2.3. These data suggest a sensory-sympathetic reflex, where SP activates these peripheral sympathetic receptors with subsequent release of noradrenaline and other compounds to affect vascular cells indirectly. This control is enhanced after inflammation.
Coggeshall
Richard E
RE
Department of Anatomy and Neurosciences, Marine Biomedical Institute, University of Texas Medical Branch, Galveston, TX 77555-1069, USA.
Carlton
Susan M
SM
D000818:Animals; D001369:Axons / Q000378:metabolism; D002452:Cell Count; D005620:Freund's Adjuvant; D006614:Hindlimb / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D017779:Sympathetic Fibers, Postganglionic / Q000166:cytology / Q000378:metabolism*
D018040:Receptors, Neurokinin-1; D005620:Freund's Adjuvant