Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of a serotonin (5-HT) receptor agonist, 5-methoxy-N,N-dimethyltryptamine (5-MeODMT), on epileptic photosensitivity were studied in the lateral geniculate-kindled cat. 5-MeODMT at 4 mg/kg significantly suppressed photically induced myoclonus, but not paroxysmal EEG activity, at 0.5-1 h after injection. This antiepileptic effect was seen in association with the appearance of behavioral signs similar to those seen in the 5-HT syndrome. The present data provide further evidence that 5-HT plays an important role in photosensitive epilepsy, and suggest that the inhibitory effect of 5-MeODMT on photosensitivity results from its agonist action at 5-HT1 receptors.
 ...
PMID:Behavioral and electroencephalographic effects of a serotonin receptor agonist (5-methoxy-N,N-dimethyltryptamine) in a feline model of photosensitive epilepsy. 140 49

The administration of veratramine produced generalized tremor, myoclonus, hindlimb abduction, backward gait and Straub tail, similar to the "5-hydroxytryptamine (5-HT) syndrome", in mice. Pretreatment with metergoline, methysergide, mainserin or cyproheptadine ameliorated veratramine-induced myoclonus and tremor. For suppression of other symptoms, mianserin and cyproheptadine were effective. Metergoline improved hindlimb abduction and Straub tail, but did not inhibit backward gait. Methysergide was ineffective for the remaining symptoms. 5-Methoxy-N,N-dimethyltryptamine (5-MeODMT) enhanced all these symptoms except for Straub tail. 8-Hydroxy-2-[di-n-propylamino] tetralin hydrobromide (8-OH-DPAT) augmented tremor, hindlimb abduction and backward gait, but did not influence myoclonus and Straub tail. 5-Methoxy-3[1,2,3,6-tetrahydropyridin-4-yl] 1H-indole (RU 24969) did not modify the symptoms. Destruction of 5-HT neurons using 5,6-dihydroxytryptamine (5,6-DHT) resulted in suppression of the syndrome. The denervation supersensitivity caused by 5,6-DHT did not increase the response to veratramine. These findings indicate that part of the site of action of veratramine may be the presynaptic 5-HT neurons.
 ...
PMID:Veratramine-induced behavior associated with serotonergic hyperfunction in mice. 171 Feb 97

Investigations utilizing agonists for 5-HT receptor subtypes have been conducted to determine which 5-HT receptor subtype(s) subserve myoclonus in the guinea pig. Administration of a nonselective 5-HT agonist such as 5-MeODMT (5-HT1A/5-HT2 agonist) induces a dose-dependent behavior characterized by head jerking at low doses (1-2 mg/kg, SC) and full-blown myoclonus (continuous rhythmic whole-body jerking) at higher doses (2.5-5 mg/kg, SC). In contrast, the selective 5-HT1A receptor agonist 8-OH-DPAT and the selective 5-HT2 receptor agonist DOI do not induce myoclonus, and elicit only limited head jerking across an otherwise behaviorally active range of doses (1-5 mg/kg, SC). Importantly, the coadministration of both 8-OH-DPAT and DOI results in the emergence of dose-dependent myoclonic behavior. These data suggest that coactivation of 5-HT1A and 5-HT2 receptors may be required for the induction of myoclonus in the guinea pig.
 ...
PMID:5-HT-dependent myoclonus in guinea pigs: mediation through 5-HT1A-5-HT2 receptor interaction. 845 15

The present study examined the role of 5-hydroxytryptamine 5-HT receptor subtypes on 5-hydroxytryptamine- (5-HT-) mediated myoclonus in guinea pigs, evaluating head and whole-body jerking as two distinct behavioural responses. Myoclonus was induced by the 5-HT precursor L-5-hydroxytryptophan (L-5-HTP) and the non-selective 5-HT1A/1B/5-HT2 receptor agonist 5-methoxy-N,N-dimethyl-tryptamine (5-MeODMT). The selective 5-HT1A receptor antagonist WAY100635 (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cycloh exanecarboxamide trihydrochloride) inhibited both head and whole-body jerking. The selective 5-HT1B/1D receptor antagonist GR127935 (N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1 ,2,4-oxadiazol-3-yl)[1,1'-biphenyl]-4-carboxamide hemifumarate) only inhibited whole-body jerking, which resulted in unmasked head jerking. Co-administration of GR127935 and the selective 5-HT2A receptor antagonist MDL100.151 ((+/-)-alpha-(2,3-dimethoxyphenyl)-1-[-2-(4-fluorphenyl)ethyl]-4-+ ++piperidinmethanol) caused a complete inhibition of whole-body as well as head jerking. MDL100.151 had only limited effect on myoclonic jerking when given alone. The inhibitory effects of the 5-HT receptor antagonists on either L-5-HTP- or 5-MeODMT-induced myoclonus were found to be very similar. These data confirm a role for the 5-HT1A and 5-HT1B/1D receptors and suggest a role for 5-HT2A receptors in mediating myoclonus in guinea pigs. Moreover, the study shows that by considering head and whole-body jerking as two pharmacologically distinct behavioural responses, subtype specific 5-HT1A, 5-HT1B/1D and 5-HT2A receptor antagonists can be distinguished.
 ...
PMID:Head and whole-body jerking in guinea pigs are differentially modulated by 5-HT1A, 5-HT1B/1D and 5-HT2A receptor antagonists. 986 7