title: In vivo release of calcitonin gene-related peptide-like material from the cervicotrigeminal area in the rat. Effects of electrical and noxious stimulations of the muzzle.
abstract: The continuous perfusion with an artificial cerebrospinal fluid of the cervicotrigeminal area of the spinal cord in halothane-anaesthetized rats allowed the collection of calcitonin gene-related peptide-like material with the same immunological and chromatographic characteristics as authentic rat alpha-calcitonin gene-related peptide. The spinal release of calcitonin gene-related peptide-like material could be significantly increased by the local application of 60 mM K+ (approximately +100%), high-intensity percutaneous electrical stimulation (approximately +200%) and noxious heat (by immersion in water at 52 degrees C; approximately +150%) applied to the muzzle. By contrast, noxious mechanical (pinches) and chemical (subcutaneous formalin injection) stimulations and deep cooling (by immersion in water at 0 degrees C) of the muzzle did not alter the spinal release of calcitonin gene-related peptide-like material. In addition, low-intensity electrical stimulation, recruiting only the A alpha/beta primary afferent fibres, significantly reduced (approximately -30%) the release of calcitonin gene-related peptide-like material from the cervicotrigeminal area. These data suggest that among the various types of natural noxious stimuli, noxious heat may selectively excite calcitonin gene-related peptide-containing A delta and C primary afferent fibres projecting within the dorsal horn of the spinal cord, and that activation of A alpha/beta fibres reduces spontaneous calcitonin gene-related peptide-like material release possibly through an inhibitory presynaptic control of calcitonin gene-related peptide-containing A delta/C fibres.
authors.affiliation: Inserm U 288, Neurobiologie Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Pohl
authors.forename: E
authors.initials: E
authors.lastname: Collin
authors.forename: S
authors.initials: S
authors.lastname: Bourgoin
authors.forename: A M
authors.initials: AM
authors.lastname: Clot
authors.forename: M
authors.initials: M
authors.lastname: Hamon
authors.forename: F
authors.initials: F
authors.lastname: Cesselin
authors.forename: D
authors.initials: D
authors.lastname: Le Bars
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002850:Chromatography, Gel; D004558:Electric Stimulation; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects; D009619:Nociceptors / Q000502:physiology; D010477:Perfusion; D010812:Physical Stimulation; D011188:Potassium / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism* / Q000502:physiology; D014276:Trigeminal Nerve / Q000378:metabolism* / Q000502:physiology
chemical_list: D015740:Calcitonin Gene-Related Peptide; D011188:Potassium