Article date: 1989/11/1
PubMed ID: 2482979
Journal name: Pharmacology, biochemistry, and behavior (ISSN: 0091-3057)
Intrathecal administration of 20 micrograms of substance P induced scratching behavior in most tested rats (80%). Scratching appeared in bouts of short latency and variable duration, intensity and frequency (range 1-60, mean number of scratching bouts in one hour test: 8.93 +/- 1.86). Intrathecal administration of glycine (400 micrograms but not 66 micrograms) significantly decreased the effect of substance P on this behavior. Taurine, in dosages equimolar to glycine, abolished the response to substance P at the high dose level (700 micrograms), but did not significantly affect it at the lower level (120 micrograms). The GABAA agonist, muscimol, abolished the effect of substance P at the 3 micrograms dose level, but the 0.5 microgram dose did not produce a significant effect. Baclofen, a GABAB agonist, was highly effective in significantly reducing the action of SP at 0.9 and 0.15 microgram; only two of 8 rats receiving the low dose of baclofen (0.15 microgram) exhibited scratching. The results suggest that the spinal inhibitory amino acids modulate nociceptive impulses generated by the action of substance P in dorsal horn neurons of the spinothalamic tract.
Author List: Beyer C, Banas C, Gonzalez-Flores O, Komisaruk B R
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Receptors, Amino Acid; Receptors, Cell Surface; Receptors, GABA-A; Taurine; Muscimol; Substance P; Glycine;
Mesh terms: Animals; Behavior, Animal/drug effects; Dose-Response Relationship, Drug; Female; Glycine/administration & dosage; Injections, Spinal; Muscimol/administration & dosage; Pain/metabolism; Rats; Rats, Inbred Strains; Receptors, Amino Acid; Receptors, Cell Surface/drug effects; Receptors, GABA-A/drug effects; Substance P/pharmacology; Taurine/administration & dosage;