title: Observations on chloralose-induced myoclonus in guinea-pigs.
abstract: 1 The physiological, biochemical and pharmacological features of alpha-chloralose-induced myoclonus in the guinea-pig have been studied. 2 EMG bursts in muscles jerking in chloralose-induced myoclonus are long, and are not time-locked to any cortical event recorded in the EEG, although they are evoked by auditory or peripheral nerve stimuli. 3 The efferent conduction velocity down the spinal cord of the signals generating the EMG bursts is fast but the afferent conduction velocity up the cord for stimulus-evoked jerks is slow, in distinction to the reverse characteristics of the spino-bulbo-spinal relfex arc. 4 alpha-Choralose did not cause any consistent change in 5-hydroxytryptamine (5-HT) or 5-hydroxyindoleacetic acid levels in any brain area, nor did it alter 5-HT turnover as judged by the depletion of 5-HT after p-chlorophenylalanine pretreatment. 5 Pretreatment of animals with drugs that increase brain 5-HT action (L-tryptophan with a monoamine oxidase inhibitor, or 5-hydroxytryptophan), or antagonize the action of 5-HT (cyproheptadine) did not abolish or obviously increase chloralose-induced myoclonus. 6 Chloralose-induced myoclonus is not similar to 5-HT-sensitive reticular reflex myoclonus in man.
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D002698:Chloralose / Q000494:pharmacology*; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006168:Guinea Pigs; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D009207:Myoclonus / Q000139:chemically induced*; D012701:Serotonin / Q000378:metabolism
chemical_list: D002698:Chloralose; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid