Νευροφαρμακολογία και λειτουργική ανατομία των βασικών γαγγλίων του εγκεφάλου: Πειραματική μελέτη σε επίμυες

The most extensively used test for the investigation of neostriatal dopaminergic function is the rotating rat model. During the past several years however it has become apparent that the neostriatum is not an homogeneous structure. Thus in order to investigate regional differences within striatum concerning asymmetric locomotor behaviours, rats with unilateral, total, dorsal or ventral ibotenic acid induced striatal lesions were challenged systematically with various DA and GABA related drugs. In rats with total lesions DA drugs induced an intense ipsilateral rotation, but rats bearing lesions of the dorsal or ventral striatum exhibited different patterns of rotational behaviour. These differences were largely attributed to the distinct topographic localisation of the two major striatal efferent systems within the striatum. It is well established that intrastriatal dopaminergic activity is mediated through the GABAergic striatal efferents projecting mainly to subtantia nigra zona reticulata and globus pallidus. In subsequent experiments local intracaudate injections of the GABA agonist muscimol or the GABA antagonist picrotoxin in d-amp treated rate also revealed differences between dorsal and ventral striatum, pointing out a complex interaction between DA receptor subtypes and GABAergic striatal efferents. It is widely accepted that both D1 and D2 dopamine receptors play a role in dopaminergic activity in the basal ganglia. In an attempt to relate the observed differences to the two DA receptor subtypes we examined the topography of D1- and D2- mediated rotation following localised intrastriatal injections of selective DA related drugs. The results showed that D1 receptors mediate rotation only in ventral striatum, while D2 receptors in both striatal regions. Thus it could be postulated that the two DA receptors may relate to differential striatal efferents. In order to clarify the issue, rats bearing a unilateral lesion of the globus pallidus or the subtantia nigra zona reticulata, received intrastriatal injections of D1- or D2- selective drugs, or the GABA agonist muscimol. The results revealed that globus pallidus is essential for the expression of D2-mediated rotation elicited in the dorsal striatum, while subtantia nigra is essential for the expression of D1-mediated rotation elicited in the ventral striatum. On the basis of these results, it is suggested that the neostriatum can be subdivided into a ventral, limbic-afferented region and a dorsal non-limbic region which give rise to different output lines; the ventral sector projecting (through D1-receptor activation) to subtantia nigra, and the dorsal portion mainly projecting (through D2-receptor activation) to globus pallidus. Finally, the possible clinical use of the new D1- and D2- selective drugs is examined.

Grantor dc:publisher

University of Ioannina

Year dc:date

1990

Authors dc:creator

• Konitsiotis, Spyridon
• Κονιτσιώτης, Σπυρίδων

• G Γ-αμινοβουτυρικό οξύ
• Αγωνιστές ντοπαμίνης
• Ανταγωνιστές ντοπαμίνης
• Ενδεγκεφαλικές βλάβες
• Ενδεγκεφαλικές εγχύσεις
• Μέλαινα ουσία
• Ραβδωτό σώμα
• Συμπεριφορά περιστροφής
• Υποδοχείς ντοπαμίνης
• Ωχρά σφαίρα
• Cerebral lesions
• Corpus striatum
• Dopamine agonists
• Dopamine antagonists
• Dopamine receptors
• GABA
• Globus pallidus
• Ibotenic acid
• Rotational behavior
• SUBTANTIA NIGRA
• Ιατρική και Επιστήμες Υγείας
• Βασική Ιατρική
• Medical and Health Sciences
• Basic Medicine

Language dc:language

gre

Identifier

10.12681/eadd/1331

OAI identifier oai:identifier

oai:10442/1331