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)

A behavioural study on the effects of D1 and D2 dopamine receptor antagonists (SCH 23390 and sulpiride respectively) and of an A1 adenosine receptor agonist (N6-L-phenylisopropyladenosine, L-PIA) against phencyclidine (PCP)-induced effects was assessed in adult male rabbits. SCH 23390 (0.003-0.01 mg/kg i.v.) and sulpiride (12.5 mg/kg i.v.) were able to significantly prevent PCP-induced stereotypy. Ataxia was reduced by SCH 23390 (0.003 mg/kg i.v.), while it was potentiated by sulpiride (12.5 mg/kg i.v.). Given alone at 12.5 mg/kg, sulpiride induced some EEG and behavioural effects in rabbits, while SCH 23390 (0.003 and 0.01 mg/kg) did not. L-PIA prevented both PCP-induced stereotypy and ataxia at the dose (0.1 mg/kg i.v.) devoid of behavioural or EEG effects by itself. Our results suggest that D1 dopamine receptors might play a more important role than D2 receptors in the expression of PCP-induced behaviour. They also propose that A1 adenosine receptors might be involved (e.g. via an influence on the dopamine release) in the behavioural effects of PCP.
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PMID:Evidence of the involvement of D1 dopamine receptors in PCP-induced stereotypy and ataxia in rabbits. 218 22

Acute and 1-month toxicity studies with SCH 31846, a nonsulfhydryl anti-hypertensive agent which acts by inhibiting angiotensin-converting enzyme, were initiated to evaluate its toxicity. The oral LD50s in mice and rats were approximately 1.8 and 2.5 g/kg, respectively, while the iv LD50 was approximately 450 mg/kg in mice and 150 mg/kg in rats. Signs of acute toxicity in rats and mice included salivation, hypoactivity, ataxia, prostration, and convulsions. In a 1-month dog study at oral doses of 25, 75, or 150 mg/kg, there was a dose-related increase in emesis between 1 and 2 hr after dosing. Absorption studies showed peak blood concentrations occurring in dogs between 0.3 and 1 hr after dosing. No other noteworthy antemortem changes were observed. In a 1-month rat study at oral doses of 30, 180, or 600 mg/kg, the hematocrit and hemoglobin values of the 600 mg/kg-dosed female rats were slightly but significantly (p less than 0.05) decreased and the blood urea nitrogen was slightly but significantly (p less than 0.05) increased in all SCH 31846-dosed male rats and the 600 mg/kg-dosed female rats. Absorption studies in male rats at doses of 30, 180, and 600 mg/kg indicate that SCH 31846 is well absorbed in rats. The 150 mg/kg-dosed dogs and the 180- and 600 mg/kg-dosed rats had a slight increase in the number of renin-containing granules in the renal juxtaglomerular cells. No other compound-related microscopic changes were observed. These data are similar to data reported for Captopril and suggest that in the dog and rat the toxicity of ACE inhibitors is not dependent upon the presence or absence of a sulfhydryl group.
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PMID:Acute and subchronic toxicity of a nonsulfhydryl angiotensin-converting enzyme inhibitor. 300 64

Low doses of the uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) induce locomotor stimulation in mice, whereas higher doses are associated with ataxia, stereotyped behaviors and catalepsy. We investigated the role of dopamine receptors and presynaptic dopamine neurons in the locomotor effects of dizocilpine. For comparison, we studied several other drugs that induce locomotor stimulation in mice. Pretreatment of male mice with haloperidol (0.1 mg/kg, i.p.) completely prevented the stimulation of normally coordinated locomotion induced by a non-intoxicating dose of dizocilpine (0.1 mg/kg, i.p.); haloperidol also attenuated the locomotor stimulation produced by phencyclidine (PCP, 1 and 2 mg/kg, i.p.), d-amphetamine (2 and 5 mg/kg, i.p.) and diazepam (0.5 mg/kg, i.p.). Haloperidol (doses up to 2.5 mg/kg) did not attenuate the ataxia and decreased locomotion induced by higher doses of dizocilpine (1 and 2 mg/kg). The active cis isomer of flupenthixol (0.5 mg/kg, i.p.), an antagonist of both D1 and D2 dopamine receptors, also diminished the stimulant actions of all of the test drugs, whereas its inactive trans form did not. The selective D1 antagonist R(+/-)-SCH 23390 (0.1 mg/kg) and the selective D2 antagonist raclopride (1 mg/kg) had little effect on the stimulatory effect of dizocilpine, although they did reduce the stimulation produced by PCP, d-amphetamine and diazepam. However, pretreatment with a combination of R(+/-)SCH 23390 and raclopride completely prevented dizocilpine-induced locomotor stimulation. Pretreatment with alpha-methyl-p-tyrosine (AMPT, 50 and 250 mg/kg), an inhibitor of tyrosine hydroxylase, or with 6-hydroxydopamine (6-OH-DA, 50 micrograms, i.c.v.), a neurotoxin that destroys brain dopaminergic and noradrenergic neurons, did not attenuate the locomotor stimulation induced by dizocilpine, although these treatments did reduce the stimulant effects of d-amphetamine. In AMPT or 6-OH-DA pretreated mice, haloperidol (0.125 mg/kg) prevented the stimulatory effect of dizocilpine. These results support a role for dopamine receptors in the stimulation of normally coordinated locomotion by dizocilpine. However, the locomotor stimulant effect of dizocilpine, unlike that of d-amphetamine, can be expressed in the presence of D1 or D2 dopamine receptor blockade and does not appear to be dependent on intact presynaptic mechanisms.
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PMID:Effects of D1 and D2 dopamine receptor antagonists and catecholamine depleting agents on the locomotor stimulation induced by dizocilpine in mice. 856 5

The effects of dopamine receptor antagonists on phencyclidine (PCP)-induced behaviors were examined in rats. Acute administration with PCP (7.5 mg/kg i.p.) produced various behavioral changes, such as increases of spontaneous activity, head-weaving, sniffing, rearing, back-pedaling, and ataxia. To determine which dopamine receptor subtypes were involved in mediating the PCP-induced behaviors, SCH 23390 (0.05 and 0.5 mg/kg), sulpiride (20 and 100 mg/kg), or haloperidol (0.05 and 0.5 mg/kg) were pretreated 30 min before PCP treatment (7.5 mg/kg). A higher dose of SCH 23390 significantly reduced the increase of spontaneous activity induced by PCP. Both doses of sulpiride did not affect the PCP-induced behaviors. A higher dose of haloperidol decreased the PCP-induced spontaneous activity, whereas a lower dose of haloperidol enhanced the activity. Ketanserin (0.5 and 5 mg/kg) did not alter any PCP-induced behaviors. These results suggest that the D1, but not D2, dopamine receptor subtype may be involved in the PCP-induced behavioral abnormality.
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PMID:Involvement of dopamine D1 receptors in phencyclidine-induced behavioral stimulation in rats. 866 36

In the apomorphine-induced climbing mouse assay, the potencies of the selective adenosine A1 receptor agonist, N6-cyclohexyladenosine (CHA), and the selective A2A adenosine receptor agonist, 2-p-(2-carboxyethyl) phenethylamino 5'-N-ethyl-carboxamidoadenosine (CGS 21680), and various dopamine receptor antagonists were as follows: SCH 23390 = haloperidol > raclopride > CHA = CGS 21680. While in catalepsy, their potencies were SCH 23390 > haloperidol > raclopride > CGS 21680. CHA failed to induce catalepsy due to significant sedation/ataxia. The combined administration of the ED15 dose of CHA failed to potentiate the ED50 value of SCH 23390, raclopride, or haloperidol in the apomorphine-induced climbing mouse assay. However, the combined administration of the ED15 dose of CGS 21680 significantly decreased the ED50 of raclopride by 8.0-fold and haloperidol by 35-fold. The adenosine A2A receptor antagonist, 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), significantly decreased catalepsy induced by raclopride and haloperidol, while the adenosine A1 receptor antagonist, 1,3-dimethyl-8-phenylxanthine (8-PT), was ineffective. The present results show that in behavioral assays predictive for antipsychotic activity, adenosine receptor agonists block behaviors in a similar manner to dopamine receptor antagonists.
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PMID:Selective adenosine A2A receptor/dopamine D2 receptor interactions in animal models of schizophrenia. 872 May 78

We examined the involvement of multiple monoaminergic receptors in the induction of spontaneous tail-flicks (STFs) by the open channel blocker at N-methyl-D-aspartate (NMDA) receptors, dizocilpine, and the NMDA recognition site antagonist 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP). At doses eliciting a maximal STF response, dizocilpine and CPP elevated levels of norepinephrine, but not dopamine or serotonin, in dialysates of nucleus accumbens, their known locus of action in eliciting STFs. Chemically diverse alpha(2)-adrenergic receptor (AR) antagonists atipamezole, L745,743, RX821,002, idazoxan, and desfluparoxan abolished induction of STFs by dizocilpine, whereas the preferential alpha(1)-AR antagonists prazosin, WB4101, and ARC239 were weakly active: relative potencies in blocking STFs correlated significantly with affinity at alpha(2)-ARs. The D(1)/D(5) receptor antagonists SCH23390, SCH39166, and NNC756 potently abolished STFs, whereas the D(2) antagonist L741,626, the D(3) antagonists GR218,231 and S14297, and the D(4) antagonists S18126 and L745,870 were inactive. D(1) and alpha(2)-AR antagonists also blocked induction of STFs by CPP. Blockade of dizocilpine-induced STFs was specific inasmuch as idazoxan and SCH 23390 did not modify induction of ataxia by dizocilpine. Antagonists at multiple 5-hydroxytryptamine receptors failed to modify induction of STFs. Finally, dizocilpine-induced STFs were blocked by clozapine and 11 other antipsychotics, the potency of which correlated significantly with affinity at alpha(2)-ARs. In conclusion, STFs evoked by interruption of transmission at NMDA receptors are dependent on D(1) receptors and alpha(2)-ARs for their expression. Antagonism of the alpha(2)-ARs is involved in their blockade by antipsychotics. This model should facilitate exploration of interrelationships between glutamatergic and monoaminergic mechanisms involved in psychiatric and neurologic disorders.
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PMID:Induction of spontaneous tail-flicks in rats by blockade of transmission at N-methyl-D-aspartate receptors: roles of multiple monoaminergic receptors in relation to the actions of antipsychotic agents. 1064 Mar 5

1. Administration of MK-801 a selective antagonist of the NMDA receptors (50, 100 and 150 micrograms/kg, s.c.) elicited in adult cats ataxia and loss of equilibrium. A dose-response effect was observed. 2. Administration of DNQX, a selective antagonist of the non-NMDA receptors, even with doses 20 times higher than those employed with MK-801, did not produce any behavioural disturbances. 3. Previous injection of SCH 23390, a selective parenteral antagonist of dopamine D1 receptor, reduced significantly the intense ataxic effects of MK-801, while sulpiride only increased the latency of the symptoms. 4. The results are discussed considering the reported interactions between the dopaminergic and glutamatergic systems.
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PMID:Behavioural motor effects of MK-801 and DNQX parenteral administration in adult cats: dose-response analysis. Modulatory role of dopaminergic D1 and D2 antagonists on MK-801 induced motor behaviours. 1078 56