Open AccessSome correlations between procaine-induced convulsions and monoamines in the spinal cord of rats.
Author(s) -
Kohei Sawaki,
Mitsuru Kawaguchi
Publication year - 1989
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.51.369
Subject(s) - procaine , monoamine neurotransmitter , spinal cord , chemistry , serotonin , serotonergic , medicine , endocrinology , convulsant , dopamine , dopaminergic , anesthesia , receptor , psychiatry
The relationships between the convulsions induced by the local anesthetic procaine and monoamines in the spinal cord were investigated in rats. The levels of dopamine (DA) and serotonin (5-HT) in the spinal cord were time-dependently increased after procaine (170 mg/kg, i.p.), which induced clonic convulsions, but the level of norepinephrine (NE) was unchanged. The rats that died during convulsions had a marked increase in DA. Phenobarbital (25 mg/kg, s.c.) produced both depletion of DA and elevation of 5-HT in the spinal cord and completely protected rats against convulsions. A 5-HT precursor, 5-hydroxytryptophan (5-HTP; 20-80 mg/kg, i.p.), suppressed the convulsions in a dose-dependent manner as shown by a decrease in the incidence and a prolongation of the latency, but a DA precursor, 3,4-dihydroxyphenylalanine (L-DOPA; 20-80 mg/kg, i.p.), markedly shortened the latency. Furthermore, the effect of L-DOPA on the convulsions was inhibited by the combination of 5-HTP. alpha-Methyl-p-tyrosine (20-80 mg/kg, i.p.) or DL-p-chlorophenylalanine (20-80 mg/kg, i.p.), an inhibitor of NE and DA or 5-HT biosynthesis, had a slight effect on the convulsions. These results suggest that procaine causes significant elevations of rat spinal DA and 5-HT in the convulsive process and suggest that dopaminergic and serotonergic neurons may be associated with procaine-induced convulsions.