The unilateral, intranigral administration of muscimol produced a spontaneous circling, contralateral to the injected side, lasting from 90 min to several h, according to the dose (5, 25, 50 ng/s.n.). This contralateral circling was potentiated by haloperidol (0.2 mg/kg) and antagonized by apomorphine. The bilateral injection of muscimol in the s.n. resulted in stereotyped movements which were resistant to haloperidol administration. Moreover, haloperidol (up to 5 mg/kg) failed to produce catalepsy in these bilaterally injected rats. Picrotoxin, injected unilaterally in the nigra in a dose of 20 ng, produced ipsilateral turning, which was potentiated by apomorphine (0.2 mg/kg) and antagonized by haloperidol administered in the contralateral striatum. The bilateral injection of the same dose of picrotoxin induced rigid catalepsy, which was not sensitive to apomorphine treatment (0.20 mg/kg). Both the contralateral turning and the stereotypes induced by the acute, intranigral administration of muscimol were very similar to the chronic effects elicited by intranigral kainic acid (k.a.) observed from 24 h to several days after treatment, a compound that destroys rather selectively the neurons of the pars reticulata. Conversely, the acute effect of the unilateral injection of k.a., which is supposed to be initially stimulatory, recalled the effect of intranigral picrotoxin. The following neuronal model is proposed: the nigral, k.a. sensitive neurons control posture in a manner opposite to striatal dopamine. The function of the nigro-striatal dopamine system is to inhibit these neurons by activating a strio-nigral GABAergic pathway. © 1978.

Olianas, M.C., De Montis, M.G., Mulas, G., Tagliamonte, A. (1978). The striatal dopaminergic function is mediated by the inhibition of a nigral, non-dopaminergic neuronal system via a strio-nigral GABAergic pathway. EUROPEAN JOURNAL OF PHARMACOLOGY, 49(3), 233-241 [10.1016/0014-2999(78)90098-5].

The striatal dopaminergic function is mediated by the inhibition of a nigral, non-dopaminergic neuronal system via a strio-nigral GABAergic pathway

De Montis, M. G.;Tagliamonte, A.
1978-01-01

Abstract

The unilateral, intranigral administration of muscimol produced a spontaneous circling, contralateral to the injected side, lasting from 90 min to several h, according to the dose (5, 25, 50 ng/s.n.). This contralateral circling was potentiated by haloperidol (0.2 mg/kg) and antagonized by apomorphine. The bilateral injection of muscimol in the s.n. resulted in stereotyped movements which were resistant to haloperidol administration. Moreover, haloperidol (up to 5 mg/kg) failed to produce catalepsy in these bilaterally injected rats. Picrotoxin, injected unilaterally in the nigra in a dose of 20 ng, produced ipsilateral turning, which was potentiated by apomorphine (0.2 mg/kg) and antagonized by haloperidol administered in the contralateral striatum. The bilateral injection of the same dose of picrotoxin induced rigid catalepsy, which was not sensitive to apomorphine treatment (0.20 mg/kg). Both the contralateral turning and the stereotypes induced by the acute, intranigral administration of muscimol were very similar to the chronic effects elicited by intranigral kainic acid (k.a.) observed from 24 h to several days after treatment, a compound that destroys rather selectively the neurons of the pars reticulata. Conversely, the acute effect of the unilateral injection of k.a., which is supposed to be initially stimulatory, recalled the effect of intranigral picrotoxin. The following neuronal model is proposed: the nigral, k.a. sensitive neurons control posture in a manner opposite to striatal dopamine. The function of the nigro-striatal dopamine system is to inhibit these neurons by activating a strio-nigral GABAergic pathway. © 1978.
1978
Olianas, M.C., De Montis, M.G., Mulas, G., Tagliamonte, A. (1978). The striatal dopaminergic function is mediated by the inhibition of a nigral, non-dopaminergic neuronal system via a strio-nigral GABAergic pathway. EUROPEAN JOURNAL OF PHARMACOLOGY, 49(3), 233-241 [10.1016/0014-2999(78)90098-5].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/30320
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