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

Although numerous subtypes of serotonin [5-hydroxytryptamine (5-HT)] receptors have been identified in the newborn rat by radioligand binding studies, there have been few studies of the functional significance of these early receptors, most without the benefit of selective drugs. We performed acute dose-response and time course behavioral studies in 1-day-old rats with the putative selective agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (5-HT1A), 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)1H-indole (RU 24969) (5-HT1B), and (+-)1-(2,5-dimethoxy-4-iodo-phenyl aminopropane)-2 (DOI) (5-HT2/1C). The agonists induced distinctive behavioral syndromes. The DOI syndrome mainly included rudiments of forepaw myoclonus and dystonic limb postures, but no shaking behavior (head shakes or wet-dog shakes) or spinal myoclonus, two key reference behaviors for its effects in adult rats. The most distinctive feature of the 8-OH-DPAT-induced syndrome was flat body posture. RU 24969 most significantly increased locomotor activity, inducing propulsive movements with episodic rests and sudden hindlimb jerks. These studies suggest that functional and differential activity of 5-HT1A, 5-HT1B, and 5-HT2/1C receptors occurs much earlier in the rat than previously appreciated. The absence of DOI-induced shaking behavior and spinal myoclonus, however, suggests incomplete maturation at the level of the receptor or effector pathways for these behaviors.
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PMID:Serotonin receptor ontogeny: effects of agonists in 1-day-old rats. 147 12

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.
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PMID:Veratramine-induced behavior associated with serotonergic hyperfunction in mice. 171 Feb 97

Myoclonic jerking in guinea pigs originates from the brainstem. Indole-containing 5-hydroxytryptamine (5-HT) agonists, but not piperazine-containing 5-HT agonists, induced myoclonus in guinea pigs at pharmacologically relevant doses. Guinea pig brainstem preparations possessed specific binding sites for [3H]5-HT but specific [3H]spiperone binding was low and inconsistent. 5-HT-1 receptors appear to predominate in this tissue. High affinity [3H]5-HT binding was potently displaced by indole-containing 5-HT agonists but only weakly displaced by piperazine-containing 5-HT agonists. The [3H]5-HT specific binding site in guinea pig brainstem responsible for the induction of indoleamine-dependent myoclonus has the characteristics of a 5-HT-1 receptor.
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PMID:5-Hydroxytryptamine (5-HT)-dependent myoclonus in guinea pigs is induced through brainstem 5-HT-1 receptors. 672 93

In guinea pigs, myoclonus can be induced by 5-hydroxytryptamine (5-HT, serotonin) precursors and synthetic 5-HT receptor agonists, yet the receptor subtype specificity of this behavior is not fully delineated. Guinea pigs were pre-treated with carbidopa (50 mg) followed by one of eight 5-HT antagonists: (-)-N-tert-butyl-3-[4-(2-methoxyphenyl) piperazin-1-yl]-2-phenyl propionamide ((-)-WAY 100135) (5-HT1A), N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]-ethyl]-N-(2-pyridyl)-cy clohexancarboxamide (WAY 100635) (5-HT1A), methiothepin mesylate (5-HT1/2), mesulergine hydrochloride (5-HT2A/2C), N[4-methoxy-3-(4-methyl-L-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2 ,4-oxadizol-3-yl) (GR 127935) (5-HT1D), trans-4-[(3Z)3-(2-dimethylaminoethyl)oxyimino-3(2-fluorop hen yl) propen-1-yl]phenol, hemifumarate (SR 46349) (5-HT2), ondansetron hydrochloride (5-HT3), and [1-[2-[methylsulphonyl)amino]ethyl]-4-piperidinyl]methyl-5-fluoro-2-meth oxy-1H-indole-3-carboxylate (GR 125487) (5-HT4). Thirty minutes later, they received 5-hydroxytryptophan (5-HTP) (75 mg/kg, sc) and myoclonic jumping rates were assessed every 10 min for 200 min by a blinded observer. Repeated measures analysis of variance of drug-induced antagonism of 5-HTP-induced myoclonus revealed a significant effect for the 5-HT receptor antagonists methiothepin mesylate, GR127935, and mesulergine hydrochloride compared to placebo, and each of these drugs inhibited 5-HTP-induced myoclonus in a dose-dependent fashion. Based on the receptor profiles of the three effective antagonists, 5-HTP-induced myoclonus is influenced by the 5-HT1/2 receptor systems. The absence of a significant change with any other receptor subtype antagonist suggests that myoclonus is not related to diffuse activation of central serotonergic mechanisms.
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PMID:5-Hydroxytryptophan-induced myoclonus in guinea pigs: mediation through 5-HT1/2 receptor subtypes. 965 Aug 47