Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Guinea pigs treated with a single s.c. injection of a slowly released morphine suspension (300 mg/kg) exhibited a quantifiable withdrawal syndrome after naloxone injection (0.01-10 mg/kg s.c.). Ileum removed from such animals responded to naloxone (1-300 ng/ml) by contracting. These contractions could be blocked by scopolamine or tetrodotoxin. Both the in vivo and in vitro responses were specific for the opiate-dependent state and were dependent on naloxone dose. Time courses of the development and decline of the two responses were similar. Weaker opioids, pentazocine and codeine, were less effective than morphine in producing a dependent state and sensitizing ileum to naloxone. 1-(-)-delta9-Tetrahydrocann abinol [1-(-)-delta9-THC] antagonized the effect of naloxone on ileum without affecting responses to acetylcholine. 1-(-)-delta9-THC produced a stereospecific, dose-dependent (1-10 mg/kg p.o.) inhibition of naloxone-precipitated withdrawal in guinea pigs and rats that was more complete than and different from that produced by sedatives. Pentobarbital inhibited withdrawal only at doses that produced ataxia. 1-(-)-delta9-THC had a biphasic effect on locomotor activity of guinea pig in the dose range that inhibited withdrawal, stimulation at 1 mg/kg and depression at 3 to 10 mg/kg. Our results suggest that cannabinoids may be useful in opiate detoxification. The inhibition by 1-(-)-delta9-THC of the action of naloxone in "dependent" ileum seems to be via reduction in acetylcholine release. Whereas the end result of 1-(-)-delta9-THC action in brain may not necessarily be a reduction in acetylcholine release as in ileum, the mechanism by which it produces this effect in the ileum model may explain its ability to antagonize withdrawal.
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PMID:Correlation between the in vivo and an in vitro expression of opiate withdrawal precipitated by naloxone: their antagonism by l-(-)-delta9-tetrahydrocannabinol. 98 78

11-Methy-delta8-, 9-nor-delta8, and 9-nor-delta9-tetrahydrocannabinol (THC), newly synthesized cannabinoids which are not 11-hydroxyated in vivo, were tested for cannabinoid activity. Delta8-, delta9-THC and each synthetic analog produced static ataxia in unanesthetized dogs, hypotension and bradycardia in anesthetized dogs, and decreased spontaneous activity in mice. All synthetic analogs tested produced a greater degree of tolerance to the behavioral effect in dogs than did delta8-THC. 11-Methyl-delta8-THC was more effective than delta8-THC in decreasing spontaneous activity in mice, but was less active in producing the behavioral and cardiovascular effects in dogs. 9-nor-delta9-THC was less active than delta9-TCH, but 9-nor-delta8-THC was as active as delta8-THC in all observations. These results suggest that the 11-hydroxy metabolites of delta8- and delta 9-THC are not solely responsible for the biological activity of tetrahydrocannabinol.
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PMID:Marihuana-like activity of new synthetic tetrahydrocannabinols. 120 25

The present experiments were conducted to investigate the effects of four cannabimimetics on detailed temporal parameters of operant responding. In this study, the behavioral output during performance of a fixed ratio 5 schedule of reinforcement was recorded by a computer program that measured the response initiation time (IT; time interval between the offset of one lever press and the onset of the next) and the response duration (the amount of time that elapses from the onset to the offset of one lever press) of each lever press. ITs were further partitioned into fast responses (IT=0.0-1.0 s), short pauses (IT= 1.0-2.5 s), and long pauses (IT>2.5 s). Four cannabimimetic agents were assessed in this study: (R)-methanandamide (AM 356), a hydrolytically stable analog of arachidonylethanolamide, an endogenous ligand for the CB1 receptor; CP-55,940, a potent non-classical synthetic ligand; (-)-delta8-tetrahydrocannabinol (delta8-THC), an isomer of the naturally occurring delta9-THC; and WIN 55,212-2, a synthetic aminoalkylindole. All four of the cannabimimetic drugs tested significantly suppressed operant lever pressing in a dose dependent manner. The rank order of potencies observed in the present study was CP-55,940>>WIN-55,212-2>delta8-THC>AM 356, which is consistent with the rank order of affinities for the CB1 receptor shown by these drugs. All of the cannabimimetics substantially increased average IT, and also increased duration time. There was a substantial increase in average length of long pauses, and statistically significant but very small changes in the local rate of responding as measured by the average length of fast ITs. Cannabinoid-treated rats were largely immobile during pauses in responding, and these animals showed several signs of ataxia and catalepsy at the doses that suppressed lever pressing. Together with other data, the present results suggest that CB1 stimulation leads to motor effects that are associated with a suppression of lever pressing.
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PMID:A detailed characterization of the effects of four cannabinoid agonists on operant lever pressing. 963 1

We have recently reported that mediation of intracerebellar nicotine-induced attenuation of cerebellar delta9-THC ataxia was via the alpha4beta2 nAChR. The present study was meant to investigate the role of cerebellar nitric oxide (NO)-guanylyl cyclase (GC) signaling in the alpha4beta2-mediated attenuation in CD-1 male mice. Drugs were given via intracerebellar microinfusion using stereotaxically implanted guide cannulas, with ataxia evaluated by Rotorod. Intracerebellar microinfusion of SNP (sodium nitroprusside, NO donor; 15, 30, 60 pg) and SMT (S-methylisothiourea, inhibitor of inducible NO synthase; 70, 140, 280 fg) significantly enhanced and reduced, respectively, intracerebellar RJR-2403 (selective alpha4beta2 agonist)-induced attenuation of delta9-THC ataxia dose-dependently. Intracerebellar isoliquiritigenin (GC-activator; 1, 2, 4 pg) and ODQ (1H[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, GC inhibitor; 200, 400, 800 fg), significantly enhanced and reduced, respectively, intracerebellar RJR-2403-induced attenuation of delta9-THC ataxia dose-dependently. Further support for the role of NO was evidenced via increases in cerebellar NO(x) (nitrate+nitrite) levels following microinfusion of nicotine or RJR-2403 as compared to control, whereas delta9-THC significantly decreased NO(x) levels. "Nicotine/RJR-2403+delta9-THC" treated mice had cerebellar NO(x) levels significantly increased as compared to mice infused with delta9-THC alone. Results of the present investigation support the role of cerebellar NO-GC signaling in alpha4beta2 nAChR subtype-mediated attenuation of delta9-THC ataxia.
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PMID:Involvement of the alpha4beta2 nicotinic receptor subtype in nicotine-induced attenuation of delta9-THC cerebellar ataxia: role of cerebellar nitric oxide. 1727 78

Cannabis is one of the most widely used recreational drugs in the world. Tetrahydrocannabinol (THC) is the psychoactive principal constituent of the cannabis plant (Cannabis sativa). It is taken either orally or by inhalation, resulting in sedation, euphoria, relaxation and loss of social inhibition. Adverse effects from higher doses can include fear, distrust and a profound state of unease, hallucinations, ataxia, stupor and seizures. Long-term use can result in respiratory and cardiovascular toxicity and has been associated with a range of psychiatric conditions. Cannabinoid hyperemesis syndrome can occur with chronic use. Driving under the influence of THC is associated with approximately double the risk of motor vehicle crashes. The intensity and duration of symptoms is proportional to the concentration of THC in the blood. Following acute use, THC only remains in the blood for several hours before it is converted into a carboxylic derivative of THC and this partitions into the fat, from where it leaches out and can be detected in urine for weeks after use. Treatment of acute intoxication mainly consists of appropriate symptom-directed supportive care. Children are more susceptible to cannabis toxicity, particularly seizures and coma, and therefore may require additional supportive care for these potential symptoms. The aim of this narrative review is to provide a brief overview of the acute and chronic effects of cannabis, its pharmacokinetics, toxicity and the medical management of intoxication.
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PMID:The clinical toxicology of cannabis. 3303 7