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Intrastriatal dopaminergic grafts restore inhibitory control over striatal cholinergic neurons

Intrastriatal dopaminergic grafts restore inhibitory control over striatal cholinergic neurons 221 73 73 2 2 J. P. Herman A. Lupp N. Abrous M. Le Moal G. Hertting R. Jackisch INSERM-U 259, Université Bordeaux II. Domaine de Carreire Rue Camille Saint-Saëns F-33077 Bordeaux France Pharmakologisches Institut Hermann-Herder Straße 5 D-7800 Freiburg Germany Summary The aim of the study was to examine the influence of intrastriatal dopaminergic grafts on the functioning of striatal cholinergic neurons using an in vitro superfusion method. Rats bearing unilateral 6-hydroxydopamine lesion of the nigrostriatal dopaminergic system received a cell suspension obtained from ED 14 rat embryonic mesencephali which was injected into the denervated striatum. Lesioned animals displayed an ipsilateral rotation in response to amphetamine (5 mg/kg i.p.). This rotational response disappeared following grafting and there was even a significant contralateral rotation in response to the drug. Apomorphine (0.1 mg/kg s.c.) induced a contralateral rotation following the lesion. This latter response was attenuated in the grafted group. Three months after grafting 350 μm thick slices were prepared from striata from the control and experimental sides of lesioned and graft-bearing animals. The slices were preincubated either with 3 H-dopamine (10 -7 M) or 3 H-choline (10 -7 M) and then superfused with an oxygenated Krebs-Ringer solution. Stimulation with electrical pulses following preincubation with 3 H-dopamine elicited a marked increase of tritium outflow from control slices. Stimulation-evoked overflow was of similar magnitude from slices from striata containing the graft, while it was much reduced in slices from lesioned striata. Amphetamine markedly potentiated the effect of electrical stimulation in slices obtained from control and graft-containing striata. Nomifensine (a dopamine uptake blocker) led to a significant decrease of the overflow of 3 H-acetylcholine evoked by electrical stimulation from control striatal slices. This inhibition was antagonized by domperidone, a D2 dopamine receptor blocker, a finding which indicates that the action of nomifensine was indeed due to a potentiation of the action of endogenous dopamine released by the electrical stimulation. A similar, although somewhat attenuated, action of nomifensine and domperidone was observed for striatal slices containing the graft. Amphetamine inhibited the stimulation evoked overflow of 3 H-acetylcholine in a dose-dependent manner from striatal slices obtained both from the intact and experimental sides of graft-bearing animals, while it had no action on slices from denervated striata. Finally, the dose-response curve for the inhibition of 3 H-acetylcholine release by apomorphine was significantly shifted to the left for slices from the lesioned striata as compared with control slices. This leftward shift was totally abolished in the slices from the graft-containing striatum. These results indicate that the dopaminergic inhibition of the striatal cholinergic interneurons, abolished by the lesion, is restored by intrastriatal dopaminergic grafts both in vitro and in vivo. On the other hand the lack of correlation between the in vivo and the in vitro effects (rotational response vs. inhibition of 3 H-acetylcholine release) suggest that the effect of such grafts on rotational behavior cannot be explained solely by their action on the striatal cholinergic neurons. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experimental Brain Research Springer Journals

Intrastriatal dopaminergic grafts restore inhibitory control over striatal cholinergic neurons

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References (46)

Publisher
Springer Journals
Copyright
Copyright © 1988 by Springer-Verlag
Subject
Biomedicine; Neurosciences; Neurology
ISSN
0014-4819
eISSN
1432-1106
DOI
10.1007/BF00248216
Publisher site
See Article on Publisher Site

Abstract

221 73 73 2 2 J. P. Herman A. Lupp N. Abrous M. Le Moal G. Hertting R. Jackisch INSERM-U 259, Université Bordeaux II. Domaine de Carreire Rue Camille Saint-Saëns F-33077 Bordeaux France Pharmakologisches Institut Hermann-Herder Straße 5 D-7800 Freiburg Germany Summary The aim of the study was to examine the influence of intrastriatal dopaminergic grafts on the functioning of striatal cholinergic neurons using an in vitro superfusion method. Rats bearing unilateral 6-hydroxydopamine lesion of the nigrostriatal dopaminergic system received a cell suspension obtained from ED 14 rat embryonic mesencephali which was injected into the denervated striatum. Lesioned animals displayed an ipsilateral rotation in response to amphetamine (5 mg/kg i.p.). This rotational response disappeared following grafting and there was even a significant contralateral rotation in response to the drug. Apomorphine (0.1 mg/kg s.c.) induced a contralateral rotation following the lesion. This latter response was attenuated in the grafted group. Three months after grafting 350 μm thick slices were prepared from striata from the control and experimental sides of lesioned and graft-bearing animals. The slices were preincubated either with 3 H-dopamine (10 -7 M) or 3 H-choline (10 -7 M) and then superfused with an oxygenated Krebs-Ringer solution. Stimulation with electrical pulses following preincubation with 3 H-dopamine elicited a marked increase of tritium outflow from control slices. Stimulation-evoked overflow was of similar magnitude from slices from striata containing the graft, while it was much reduced in slices from lesioned striata. Amphetamine markedly potentiated the effect of electrical stimulation in slices obtained from control and graft-containing striata. Nomifensine (a dopamine uptake blocker) led to a significant decrease of the overflow of 3 H-acetylcholine evoked by electrical stimulation from control striatal slices. This inhibition was antagonized by domperidone, a D2 dopamine receptor blocker, a finding which indicates that the action of nomifensine was indeed due to a potentiation of the action of endogenous dopamine released by the electrical stimulation. A similar, although somewhat attenuated, action of nomifensine and domperidone was observed for striatal slices containing the graft. Amphetamine inhibited the stimulation evoked overflow of 3 H-acetylcholine in a dose-dependent manner from striatal slices obtained both from the intact and experimental sides of graft-bearing animals, while it had no action on slices from denervated striata. Finally, the dose-response curve for the inhibition of 3 H-acetylcholine release by apomorphine was significantly shifted to the left for slices from the lesioned striata as compared with control slices. This leftward shift was totally abolished in the slices from the graft-containing striatum. These results indicate that the dopaminergic inhibition of the striatal cholinergic interneurons, abolished by the lesion, is restored by intrastriatal dopaminergic grafts both in vitro and in vivo. On the other hand the lack of correlation between the in vivo and the in vitro effects (rotational response vs. inhibition of 3 H-acetylcholine release) suggest that the effect of such grafts on rotational behavior cannot be explained solely by their action on the striatal cholinergic neurons.

Journal

Experimental Brain Research – Springer Journals

Published: Nov 1, 1988

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