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Sensorimotor impairment and elevated levels of dopamine metabolites in the neostriatum occur rapidly after intranigral injection of 6-hydroxydopamine or gamma-hydroxybutyrate in awake rats.
- Source :
-
Neuropharmacology [Neuropharmacology] 1984 Mar; Vol. 23 (3), pp. 309-18. - Publication Year :
- 1984
-
Abstract
- The unilateral injection of 6-hydroxydopamine (8 micrograms) into the ventral tegmental area of awake rats produced a rapidly developing and irreversible sensory neglect to contralateral tactile stimuli. This neglect developed in a caudal to rostral direction on the affected body surface and coincided with significant elevation in the concentrations of dopamine and two of its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the ipsilateral neostriatum. The unilateral injection of procaine or gamma-hydroxybutyric acid (GHB) into the substantia nigra of awake animals also produced a contralateral neglect that developed in a caudal to rostral direction, but the behavioral effect of these drugs diminished within 1 hr. Concentrations of dopamine, dihydroxyphenylacetic acid and homovanillic acid in the neostriatum were markedly elevated during continuous infusions of procaine or gamma-hydroxybutyric acid. The extent of sensory neglect and changes in dopamine metabolism in the neostriatum varied according to the amount of gamma-hydroxybutyric acid injected into the nigra and according to the proximity of injections of gamma-hydroxybutyric acid to the pars compacta. The rapid onset of sensory neglect following microinjections of 6-hydroxydopamine, procaine or gamma-hydroxybutyric acid is consistent with the ability of each of these drugs to block the conduction of impulses in mesostriatal neurons and suggests that concomitant increases in levels of dopamine, dihydroxyphenylacetic acid and homovanillic acid in the neostriatum resulted from decreases in the release of dopamine coupled with increased synthesis of dopamine. These findings also indicate that the catabolism of dopamine to dihydroxyphenylacetic acid or homovanillic acid may originate intraneuronally, without prior release of dopamine and its recapture by mesostriatal terminals, if the flow of impulses in this pathway has been blocked.
- Subjects :
- 3,4-Dihydroxyphenylacetic Acid metabolism
4-Butyrolactone administration & dosage
4-Butyrolactone pharmacology
Animals
Biotransformation
Homovanillic Acid metabolism
Hydroxydopamines administration & dosage
Male
Microinjections
Oxidopamine
Procaine administration & dosage
Rats
Rats, Inbred Strains
Sodium Oxybate administration & dosage
Substantia Nigra drug effects
Corpus Striatum metabolism
Dopamine metabolism
Hydroxybutyrates pharmacology
Hydroxydopamines pharmacology
Psychomotor Performance drug effects
Sodium Oxybate pharmacology
Substantia Nigra physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0028-3908
- Volume :
- 23
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuropharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 6427648
- Full Text :
- https://doi.org/10.1016/0028-3908(84)90192-8