Abstract
The behavioral and biochemical effects of the full dopamine D 1/5 receptor agonists, dihydrexidine and (1R,3S)-1-aminomethyl-5,6- dihydroxy-3-phenylisochroman HCl (A 68930), were examined in rats. Both A 68930 (0-4.6 mg kg-1, s.c.) and dihydrexidine (0-8.0 mg kg-1, s.c.) caused a dose-dependent suppression of locomotor activity, as assessed in an open-field. This locomotor suppression was dose-dependently antagonized by the selective dopamine D1/5 receptor antagonist R(+)-7-chloro-8- hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine HCl (SCH 23390; 0-5.0 μg kg-1, s.c.), but not by the selective dopamine D 2/3 receptor antagonist raclopride (0-25.0 μg kg-1, s.c.). Furthermore, A 68930 and dihydrexidine did not cause any locomotor activity in habituated rats that displayed a very low base-line activity. Neither did A 68930 nor dihydrexidine produce any excessive stereotypies that could possibly interfere with and mask ambulatory activity. In fact, both A 68930 and dihydrexidine potently blocked hyperactivity produced by d-amphetamine (0-4.0 mg kg-1, s.c.). Such findings traditionally would be interpreted as a sign of potential antipsychotic properties of A 68930 and dihydrexidine. Examination of neuronal activation, as indexed by the immediate early gene c-fos, showed that A 68930 and dihydrexidine caused a highly significant expression of c-fos in the medial prefrontal cortex. This c-fos expression was sensitive to treatment with SCH 23390, but not with raclopride. The effects of A 68930 and dihydrexidine on c-fos expression in caudate putamen or nucleus accumbens were less marked, or undetectable. The results indicate that stimulation of dopamine D1/5 receptors, possibly in the medial prefrontal cortex, is associated with inhibitory actions on locomotor activity and d-amphetamine-induced hyperactivity. Assuming an important role of prefrontal dopamine D1/5 receptors in schizophrenia, such inhibitory actions of dopamine D1/5 receptor stimulation on psychomotor activation mya have interesting clinical implications in the treatment of schizophrenia.
| Original language | English |
|---|---|
| Pages (from-to) | 33-42 |
| Number of pages | 10 |
| Journal | Neuroscience |
| Volume | 124 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 19 2004 |
| Externally published | Yes |
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Keywords
- d-amphetamine
- Dopamine D receptor
- Immediate early gene
- Locomotion
- Rat
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
A 68930 and dihydrexidine inhibit locomotor activity and d-amphetamine-induced hyperactivity in rats : A role of inhibitory dopamine d1/5 receptors in the prefrontal cortex? / Isacson, R.; Kull, B.; Wahlestedt, Claes R; Salmi, P.
In: Neuroscience, Vol. 124, No. 1, 19.02.2004, p. 33-42.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A 68930 and dihydrexidine inhibit locomotor activity and d-amphetamine-induced hyperactivity in rats
T2 - A role of inhibitory dopamine d1/5 receptors in the prefrontal cortex?
AU - Isacson, R.
AU - Kull, B.
AU - Wahlestedt, Claes R
AU - Salmi, P.
PY - 2004/2/19
Y1 - 2004/2/19
N2 - The behavioral and biochemical effects of the full dopamine D 1/5 receptor agonists, dihydrexidine and (1R,3S)-1-aminomethyl-5,6- dihydroxy-3-phenylisochroman HCl (A 68930), were examined in rats. Both A 68930 (0-4.6 mg kg-1, s.c.) and dihydrexidine (0-8.0 mg kg-1, s.c.) caused a dose-dependent suppression of locomotor activity, as assessed in an open-field. This locomotor suppression was dose-dependently antagonized by the selective dopamine D1/5 receptor antagonist R(+)-7-chloro-8- hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine HCl (SCH 23390; 0-5.0 μg kg-1, s.c.), but not by the selective dopamine D 2/3 receptor antagonist raclopride (0-25.0 μg kg-1, s.c.). Furthermore, A 68930 and dihydrexidine did not cause any locomotor activity in habituated rats that displayed a very low base-line activity. Neither did A 68930 nor dihydrexidine produce any excessive stereotypies that could possibly interfere with and mask ambulatory activity. In fact, both A 68930 and dihydrexidine potently blocked hyperactivity produced by d-amphetamine (0-4.0 mg kg-1, s.c.). Such findings traditionally would be interpreted as a sign of potential antipsychotic properties of A 68930 and dihydrexidine. Examination of neuronal activation, as indexed by the immediate early gene c-fos, showed that A 68930 and dihydrexidine caused a highly significant expression of c-fos in the medial prefrontal cortex. This c-fos expression was sensitive to treatment with SCH 23390, but not with raclopride. The effects of A 68930 and dihydrexidine on c-fos expression in caudate putamen or nucleus accumbens were less marked, or undetectable. The results indicate that stimulation of dopamine D1/5 receptors, possibly in the medial prefrontal cortex, is associated with inhibitory actions on locomotor activity and d-amphetamine-induced hyperactivity. Assuming an important role of prefrontal dopamine D1/5 receptors in schizophrenia, such inhibitory actions of dopamine D1/5 receptor stimulation on psychomotor activation mya have interesting clinical implications in the treatment of schizophrenia.
AB - The behavioral and biochemical effects of the full dopamine D 1/5 receptor agonists, dihydrexidine and (1R,3S)-1-aminomethyl-5,6- dihydroxy-3-phenylisochroman HCl (A 68930), were examined in rats. Both A 68930 (0-4.6 mg kg-1, s.c.) and dihydrexidine (0-8.0 mg kg-1, s.c.) caused a dose-dependent suppression of locomotor activity, as assessed in an open-field. This locomotor suppression was dose-dependently antagonized by the selective dopamine D1/5 receptor antagonist R(+)-7-chloro-8- hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine HCl (SCH 23390; 0-5.0 μg kg-1, s.c.), but not by the selective dopamine D 2/3 receptor antagonist raclopride (0-25.0 μg kg-1, s.c.). Furthermore, A 68930 and dihydrexidine did not cause any locomotor activity in habituated rats that displayed a very low base-line activity. Neither did A 68930 nor dihydrexidine produce any excessive stereotypies that could possibly interfere with and mask ambulatory activity. In fact, both A 68930 and dihydrexidine potently blocked hyperactivity produced by d-amphetamine (0-4.0 mg kg-1, s.c.). Such findings traditionally would be interpreted as a sign of potential antipsychotic properties of A 68930 and dihydrexidine. Examination of neuronal activation, as indexed by the immediate early gene c-fos, showed that A 68930 and dihydrexidine caused a highly significant expression of c-fos in the medial prefrontal cortex. This c-fos expression was sensitive to treatment with SCH 23390, but not with raclopride. The effects of A 68930 and dihydrexidine on c-fos expression in caudate putamen or nucleus accumbens were less marked, or undetectable. The results indicate that stimulation of dopamine D1/5 receptors, possibly in the medial prefrontal cortex, is associated with inhibitory actions on locomotor activity and d-amphetamine-induced hyperactivity. Assuming an important role of prefrontal dopamine D1/5 receptors in schizophrenia, such inhibitory actions of dopamine D1/5 receptor stimulation on psychomotor activation mya have interesting clinical implications in the treatment of schizophrenia.
KW - d-amphetamine
KW - Dopamine D receptor
KW - Immediate early gene
KW - Locomotion
KW - Rat
UR - http://www.scopus.com/inward/record.url?scp=0442307957&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0442307957&partnerID=8YFLogxK
U2 - 10.1016/j.neuroscience.2003.11.016
DO - 10.1016/j.neuroscience.2003.11.016
M3 - Article
C2 - 14960337
AN - SCOPUS:0442307957
VL - 124
SP - 33
EP - 42
JO - Neuroscience
JF - Neuroscience
SN - 0306-4522
IS - 1
ER -