Interactions of galanin with endomorphin-2, vasopressin and oxytocin in nociceptive modulation of the trigemino-hypoglossal reflex in rats.
Galanin (GAL) is suggested to be a neuropeptide involved in pain transmission. In this study we tried to determine, whether the increase of GAL concentration in brain cells affects impulse transmission between the motor centers localized in the vicinity of the third and fourth cerebral ventricles. The experiments were carried out on rats under chloralose anesthesia. The study objectives were realized using the method allowing to record the amplitude of evoked tongue jerks (ETJ) in response to noxious tooth pulp stimulation during the perfusion of the cerebral ventricles with solutions containing tested compounds. Perfusion of the cerebral ventricles with GAL concentration-dependently inhibited the ETJ amplitude. The antinociceptive effect of GAL was blocked by a galanin receptor antagonist, galantide (GLT) and by opioid antagonists: non-selective naloxone (Nal) and micro-selective beta-funaltrexamine (beta-FNA). In contrast, a delta-opioid receptor antagonist, naltrindole (NTI) or the kappa-opioid receptor antagonist, nor-binaltrophimine (nor-BNI) did not inhibit the effect of GAL. The antinociceptive effect of GAL was more pronounced when GAL was perfused in combination with other neuropeptides/neurohormones, such as endomorphin-2 (EM-2), vasopressin (AVP) and oxytocin (OT). The present results demonstrate that in the orofacial area analgesic activity is modulated by GAL, OT and AVP and that EM-2-induced antinociception involves GAL.
Zubrzycka
M
M
Department of Experimental Physiology, Medical University of Lodz, Poland.
Janecka
A
A
D000818:Animals; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000378:metabolism*; D002552:Cerebral Ventricles / Q000378:metabolism; D003782:Dental Pulp / Q000294:innervation; D004558:Electric Stimulation; D019004:Galanin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007002:Hypoglossal Nerve / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009292:Narcotic Antagonists / Q000008:administration & dosage; D009842:Oligopeptides / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010121:Oxytocin / Q000008:administration & dosage / Q000378:metabolism*; D010146:Pain / Q000378:metabolism / Q000517:prevention & control*; D010147:Pain Measurement; D010477:Perfusion; D051381:Rats; D020318:Rats, Long-Evans; D012018:Reflex / Q000187:drug effects; D013373:Substance P / Q000008:administration & dosage / Q000031:analogs & derivatives; D014059:Tongue / Q000294:innervation*; D014276:Trigeminal Nerve / Q000187:drug effects / Q000378:metabolism*
D009292:Narcotic Antagonists; D009842:Oligopeptides; D001127:Arginine Vasopressin; C074975:galantide; D013373:Substance P; C105294:endomorphin 2; D010121:Oxytocin; D019004:Galanin