Dopaminergic denervation of the globus pallidus produces short-memory impairment in rats.

Rats with low-level globus pallidus (GP) dopaminergic denervation can develop anxiety without any motor alterations. The aim of this study was to evaluate the effect of low-level 6-OHDA-induced unilateral and bilateral GP lesions in male Wistar rats (n = 8/group) on recognition memory, motor activity, and the number of TH+ neurons in the SNc. For unilateral- and bilateral-lesioned animals, there was a significant decrease in the number of TH+ neurons (27% and 42%, respectively) and in the object, location, and temporal order discrimination indexes of recognition memory tests.

Dopamine-dependent modulation of rat globus pallidus excitation by nicotine acetylcholine receptors.

The globus pallidus (GP) coordinates information processing in the basal ganglia nuclei. The contribution of nicotinic cholinergic receptors (nAChRs) to the spiking activity of GP neurons is largely unknown. Several studies have reported that the effect of nAChRs in other nuclei depends on dopaminergic input.

6-Hydroxydopamine lesion in thalamic reticular nucleus reduces anxiety behaviour in the rat.

We have studied the effect of the lesion of the dopaminergic innervation of the thalamic reticular nucleus (TRn) on anxiety and motor behaviour. The lesion of the dopamine innervation was produced by the injection of 6-hydroxydopamine into the dorsal part of the thalamic reticular nucleus. The lesion decreased the number of TH (+) cells of the pars compacta of substantia nigra by 33%, without modifying the number of TH (+) cells in ventral tegmental area.

6-OHDA-induced hemiparkinsonism and chronic L-DOPA treatment increase dopamine D1-stimulated [(3)H]-GABA release and [(3)H]-cAMP production in substantia nigra pars reticulata of the rat.

It has been proposed that striatonigral GABAergic transmission in the substantia nigra reticulata (SNr) is enhanced during Parkinson's disease and subsequent L-DOPA treatment. To evaluate this proposal we determined the effects of activating dopamine D1 receptors on depolarization induced [(3)H]-GABA release and on [(3)H]-cAMP accumulation in slices of SNr of rats with unilateral 6-OHDA lesions with and without l-DOPA treatment. Denervation increased depolarization induced D1-stimulated [(3)H]-GABA release, while repeated L-DOPA treatment further enhanced this response.

Intranigral injection of the H3 agonist immepip and systemic apomorphine elicit ipsilateral turning behaviour in naive rats, but reduce contralateral turning in hemiparkinsonian rats.

There is evidence that histamine H3 receptors co-localise with dopamine D1 receptors on the terminals of striato-nigral neurones. In this work we studied the effect of the local activation of H3 receptors present in substantia nigra pars reticulata (SNr) on turning behaviour following apomorphine administration to either naive or hemiparkinsonian rats. In naive rats the intranigral (SNr) injection of the H3 receptor agonist immepip (3.