Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Relationship between asymmetries in striatal dopamine release and the direction of amphetamine‐induced rotation during. The first week following a unilateral 6‐OHDA lesion of the substantia nigra

Relationship between asymmetries in striatal dopamine release and the direction of... In animals with a large unilateral 6‐hydroxydopamine (6‐OHDA) lesion of the nigrostriatal dopamine (DA) system the traditional “rotational behavior model” states that amphetamine will induce circling behavior towards the denervated striatum (ipsiversive), that is, away from the side where there is greater amphetamine‐stimulated DA release and greater DA receptor stimulation. It is puzzling, therefore, why amphetamine induces contraversive rotation in rats tested 4 days after a unilateral 6‐OHDA lesion, despite a 90‐95% loss of the dopaminergic input to the striatum by this time. Rats reverse their direction of amphetamine‐induced rotation by 8 days post‐lesion and turn in the ipsiversive direction thereafter. To try and resolve this paradox, bilateral striatal microdialysis was used to estimate the effects of amphetamine on DA neurotransmission on Day 4 and Day 8 following a large unilateral 6‐OHDA lesion of the substantia nigra. On Day 4 post‐lesion, amphetamine produced a moderate (around 50% of control) increase in the extracellular concentration of DA in the denervated striatum. This amphetamine‐releasable pool of DA was exhausted by a single amphetamine challenge, because a second injection of amphetamine given 3 h after the first did not produce a comparable increase in DA. It is suggested that on Day 4 post‐lesion the amount of DA released by amphetamine in the denervated striatum is sufficient to produce greater DA receptor stimulation on that side, because of DA receptor supersensitivity, and this leads to contraversive rotation. On Day 8 post‐lesion, amphetamine induced DA release in the intact striatum but had no effect on extracellular DA in the denervated striatum (DA was nondetectable). On Day 8, therefore, DA receptor stimulation would be greatest in the intact striatum, leading to ipsiversive rotation. In conclusion, it is suggested that the seemingly paradoxical reversal in the direction of amphetamine‐induced rotation that occurs over the first week following a unilateral 6‐OHDA lesion is consistent with the traditional rotational model, and is due to time‐dependent changes in the ability of amphetamine to release DA in the denervated striatum. © 1994 Wiley‐Liss, Inc. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Synapse Wiley

Relationship between asymmetries in striatal dopamine release and the direction of amphetamine‐induced rotation during. The first week following a unilateral 6‐OHDA lesion of the substantia nigra

Loading next page...
 
/lp/wiley/relationship-between-asymmetries-in-striatal-dopamine-release-and-the-U4bNZhl0Ie

References (38)

Publisher
Wiley
Copyright
Copyright © 1994 Wiley‐Liss, Inc.
ISSN
0887-4476
eISSN
1098-2396
DOI
10.1002/syn.890170103
pmid
8042143
Publisher site
See Article on Publisher Site

Abstract

In animals with a large unilateral 6‐hydroxydopamine (6‐OHDA) lesion of the nigrostriatal dopamine (DA) system the traditional “rotational behavior model” states that amphetamine will induce circling behavior towards the denervated striatum (ipsiversive), that is, away from the side where there is greater amphetamine‐stimulated DA release and greater DA receptor stimulation. It is puzzling, therefore, why amphetamine induces contraversive rotation in rats tested 4 days after a unilateral 6‐OHDA lesion, despite a 90‐95% loss of the dopaminergic input to the striatum by this time. Rats reverse their direction of amphetamine‐induced rotation by 8 days post‐lesion and turn in the ipsiversive direction thereafter. To try and resolve this paradox, bilateral striatal microdialysis was used to estimate the effects of amphetamine on DA neurotransmission on Day 4 and Day 8 following a large unilateral 6‐OHDA lesion of the substantia nigra. On Day 4 post‐lesion, amphetamine produced a moderate (around 50% of control) increase in the extracellular concentration of DA in the denervated striatum. This amphetamine‐releasable pool of DA was exhausted by a single amphetamine challenge, because a second injection of amphetamine given 3 h after the first did not produce a comparable increase in DA. It is suggested that on Day 4 post‐lesion the amount of DA released by amphetamine in the denervated striatum is sufficient to produce greater DA receptor stimulation on that side, because of DA receptor supersensitivity, and this leads to contraversive rotation. On Day 8 post‐lesion, amphetamine induced DA release in the intact striatum but had no effect on extracellular DA in the denervated striatum (DA was nondetectable). On Day 8, therefore, DA receptor stimulation would be greatest in the intact striatum, leading to ipsiversive rotation. In conclusion, it is suggested that the seemingly paradoxical reversal in the direction of amphetamine‐induced rotation that occurs over the first week following a unilateral 6‐OHDA lesion is consistent with the traditional rotational model, and is due to time‐dependent changes in the ability of amphetamine to release DA in the denervated striatum. © 1994 Wiley‐Liss, Inc.

Journal

SynapseWiley

Published: May 1, 1994

There are no references for this article.