Norepinephrine excitation of cutaneous nociceptors in adjuvant-induced inflamed rats does not depend on sympathetic neurons.
To test the contribution of sympathetic postganglionic neurons (SPGNs) to adrenergic excitation of cutaneous nociceptor activities in adjuvant-inflamed rats (AI rats), we studied the effects of norepinephrine (NE) in a group of sympathectomized AI rats. Sympathectomy was complete in 4-6 weeks by guanethidine (30-50 mg/kg). NE excited polymodal receptor units in the saphenous nerve at an incidence (25-30%) similar to that in AI rats, while CH-38083 blocked such excitation. These results show that alpha 2-adrenoceptors in SPGNs are not involved in the norepinephrine excitation of cutaneous nociceptors in AI rats.
Sato
J
J
Department of Neural Regulation, Research Institute of Environmental Medicine, Nagoya University, Japan.
Suzuki
S
S
Tamura
R
R
Kumazawa
T
T
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001169:Arthritis, Experimental / Q000503:physiopathology*; D001599:Berberine / Q000031:analogs & derivatives / Q000494:pharmacology; D006145:Guanethidine; D008297:Male; D009431:Neural Conduction / Q000187:drug effects*; D009619:Nociceptors / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011917:Rats, Inbred Lew; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D012183:Retrograde Degeneration; D013563:Sympathectomy, Chemical; D017779:Sympathetic Fibers, Postganglionic / Q000187:drug effects / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D018341:Receptors, Adrenergic, alpha-2; D001599:Berberine; C048886:7,8-(methylenedioxy)-14-hydroxyberbane; D009638:Norepinephrine; D006145:Guanethidine