Fos and nitric oxide synthase in rat brain with chronic mesostriatal dopamine deficiency: effects of nitroglycerin and hypoxia.

We found sustained proto-oncogene c-fos expression in neurons of the lateral and medial neostriatum and suppression of this expression in nitric oxide synthase (NOS)-containing cells within the islands of Calleja after lesions of the dopaminergic mesostriatal system induced by 6-hydroxydopamine. Systemic administration of nitroglycerin (NTG) or mild hypoxia resulted in a decreased of c-fos expression in the dorsolateral part of the denervated neostriatum. However, in other brain structures NTG or mild hypoxia evoked sustained c-fos expression in NOS-containing neurons and in the sources catecholaminergic projections involved in the control of cardiovascular function.

Morphofunctional studies of the interactions of the glutamatergic, cholinergic, and dopaminergic systems in the neostriatum.

Morphological, electrophysiological, and behavioral experiments were used to study the interactions of the glutamatergic, cholinergic, and dopaminergic systems in the neostriatum of white rats with unilateral lesions of the mesostriatal dopaminergic system induced by 6-hydroxydopamine. The neostriatum was shown to contain both synaptic and interneuronal nonsynaptic interactions between these neurochemical systems. It is suggested that glutamate, which is present in excess in conditions of prolonged dopamine deficiency, has toxic effects on corticoneostriatal synaptic connections.

[Morpho-functional study of the glutamatergic, cholinergic, and dopaminergic systems interaction in the striatum].

Interaction among glutamat-, cholin-, and dopaminergic systems in the neostriatum of white rats with unilateral local lesion of the mesostriatal dopaminergic system. Both synaptic and interneuronal non-synaptic interactions among the neurochemical systems under study, were revealed.

Reversible blockade, induced by the neurotoxin MPTP, of corticofugal impulse activity to neurons of the caudate nucleus in cats.

It has been demonstrated in acute experiments in cats anesthetized with nembutal and immobilized with ditilin [succinylcholine iodide--Translator] that the number of neurons of the caudate nucleus responding to a single stimulation of the motor cortex with action potentials with a latent period less than 8.0 msec in the first 10-12 days after a course of injections of MPTP (5 mg/kg daily for 5 days, intramuscularly) decreased significantly as compared with the control. Their number is gradually restored by the 45th-54th day after the administration of the neurotoxin.

[The reversibility of a blockade of corticofugal pulse trains to the neurons of the caudate nucleus in cats evoked by the neurotoxin MPTP].

In anesthetised cats, the number of the caudate nucleus neurons responding to a cortical stimulation with latency less than 8.0 ms, increased within 10-12 days after the MPTP administration and then gradually recovers by the 45th-54th day after the neurotoxin administration. Dopamine seems to exert a protecting-inhibiting effect on transmission of corticofugal glutamatergic impulses travelling towards the neostriatum neurons.