Projections from nucleus accumbens to globus pallidus and substantia nigra in the rat

Summary Stimulation of nucleus accumbens produces inhibition and facilitation of neuronal activity in the ipsilateral globus pallidus and substantia nigra. Small lesions in the accumbens reduce pallidal but not nigral GABA content.Acknowledgment. This work was supported by an MRC grant to Prof. D. W. Straughan.     

Methiothepin and a 5-HT pathway to rat substantia nigra

Summary Methiothepin reduced both median-raphe evoked and exogenous 5-HT depression of single substantia nigra neurones. While this is compatible with a serotonin releasing pathway, additional interactions of methiothepin with exogenous dopamine suggest the need for further pharmacological confirmation.Acknowledgment. This work was supported by an MRC Programme Grant to Prof. D. W. Straughan     

Reciprocal connections between substantia nigra and medullary reticular formation in the rat

Summary Electrophysiological analysis shows reciprocal connections between substantia nigra and medullary reticular formation (nucleus reticularis giganto celullaris). The nigro-reticular connection appears to be monosynaptic, as shown by antidromic activation, and comprises an ipsi and a contralateral component. Its effect is mainly inhibitory. The reticulonigral component produces mainly excitatory effects and includes fibres from nucleus giganto celullaris and nucleus parvocelullaris in the medullary reticular formation.This work was aided by a grant from CONICIT (projecto 31.26.S1-0412).     

Monoamine oxidase activity in single nerve cell bodies from substantia nigra of rat and man

In single nerve cell bodies isolated from the substantia nigra of man and rat the active forms of MAO A and MAO B were found by the use of the microdiver technique and specific inhibitors.     

Monoamine oxidase activity in single nerve cell bodies from substantia nigra of rat and man

Summary In single nerve cell bodies isolated from the substantia nigra of man and rat the active forms of MAO A and MAO B were found by the use of the microdiver technique and specific inhibitors.     

The control of amygdaloid seizures by the globus pallidus

Summary Both in acute and chronic cats entopeduncular stimulation inhibits, to a greater extent than caudate activation, focal paroxysmal activity in the ventro-basal complex of the amygdala. Lesion of entopeduncular neurons, by means of kainic acid injection, induces a decrease of the caudate inhibitory effect. It is suggested that neostriatal control of the amygdaloid seizures occurs partly through the globus pallidus.This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Roma, Italy.     

The action of muscimol on neurones of the substantia nigra of the rat

Summary Muscimol and GABA applied microintophoretically onto nigral neurones reduce the discharge rate of most of these cells. Bicuculline reversibly antagonizes the action of muscimol. I.p. applied muscimol reduces the firing rate of about half of the nigral cells tested.The valuable assistance of Mrs Alice Fonjallaz is warmly acknowledged.     

Dopa and dopamine in the pigment of substantia nigra

Zusammenfassung Hydrolysate der Pigmentpartikel der Substantia nigra enthalten Dopa und Dopamin, jedoch kein Adrenalin, Noradrenalin oder Serotonin.

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Supported by grants from The Swedish Medical Research Council No. B71-14X-712-06A and No. B71-14X-56-07A and from The Swedish Cancer Society No. 67-111.     

Behavior modifications induced by unilateral administration of picrotoxin into rat substantia nigra]

Intranigral injection of picrotoxin in Rats induced contralateral rotation and stereotyped behaviour. These responses were significantly altered following neuroleptic treatment (haloperiod, pimozide) or ipsilateral striatal electrolytic destruction. The present results provide behavioural evidence for gamma-aminobutyric acid-mediated inhibition of the dopaminergic nigrostriatal pathway.     

A preliminary study on the behaviour and biochemical responses subsequent to the injection of 5,6-dihydroxy-tryptamine into the substantia nigra of the rat

Summary Injection of 5,7-dihydroxytryptamine into the substantia nigra of rats produces an increase of dopamine in the ipsilateral striatum, and when these animals are injected with amphetamine they do not exhibit any rotation. The mode of action of this neurotoxin is compared with that of 6-hydroxydopamine.     

A preliminary study on the behaviour and biochemical responses subsequent to the injection of 5,6-dihydroxytryptamine into the substantia nigra of the rat.

Injection of 5,7-dihydroxytryptamine into the substantia nigra of rats produces an increase of dopamine in the ipsilateral striatum, and when these animals are injected with amphetamine they do not exhibit any rotation. The mode of action of this neurotoxin is compared with that of 6-hydroxydopamine.     

Lesions in the substantia nigra of rats induce thermoregulatory deficit in the cold

Summary Rats with either electrolytic or chemical (6-hydroxydopamine) lesions in the substantia nigra displayed decreased metabolism and hypothermia when they were exposed to cold (8 °C T_a), although they showed no deficiency in thermoregulation at both moderate (22 °C) and hot (30 °C) environmental temperatures.This work was supported by grants from the Pjing-Ling Neurological Foundation (Veterans General Hospital, Taipei, Taiwan, China) and the National Science Council (Republic of China). The authors are grateful to Mr C.C. Wei for his generous support.     

Uptake of3H-GABA (γ-aminobutyric acid) and3H-leucine in the pancreatic islets and substantia nigra of the rat

Summary Isolated pancreatic islets and thin slices of substantia nigra (SN) of the rat were incubated in a medium containing³H-GABA or³H-leucine to test the activity of both tissues in the uptake of those substances. Pancreatic islets showed a low uptake of both³H-GABA and³H-leucine, but SN had a high activity in the uptake of³H-GABA, though not for³H-leucine. This suggests that GABA contained at high levels in the pancreatic islets plays some functional role other than in neurotransmission as in the central nervous system (CNS).     

Electron microscopic observations in the substantia nigra of mouse during reserpine administration

Zusammenfassung Reserpin bewirkte an den Zellen der Substantia nigra der Maus Verschwinden der Katecholamin-haltigen Granula und Anschwellen des endoplasmatischen Retikulums. Das Hauptmerkmal von normalen Kontrollzellen bildeten elektronenoptisch dichte Körper im Cytoplasma.     

Monosynaptic inhibition of thalamic neurons produced by stimulation of the substantia nigra

Summary Electrical stimulation to the substantia nigra (Pars reticulata) produced a monosynaptic inhibition of the neurons of the ventromedial necleus of the thalamus in anesthetized cats.     

Effects of penfluridol on dopamine-sensitive adenylate cyclase in corpus striatum and substantia nigra of rats

Summary Penfluridol, a neuroleptic with diphenylbutyl piperidine structure, blocked the dopamine-sensitive adenylate cyclase in homogenates of corpus striatum and substantia nigra of rats, probably by a competitive antagonism versus dopamine.Acknowledgment. We thank Dr P. Janssen (Beerse, Belgium) for a generous gift of penfluridol.     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation,in the cat

Summary The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.This work was supported by a grant from the Consiglio Nazionale delle Ricerche Roma, Italy.     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation, in the cat

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.