Transection of corticostriatal afferents reduces amphetamine- and apomorphine-induced striatal Fos expression and turning behaviour in unilaterally 6-hydroxydopamine-lesioned rats.
Corticofugal fibres from the prefrontal, prelimbic and anterior sensorimotor cortices were transected by a wide coronal knife-cut through the forceps minor. The cut was performed on the dopamine-depleted side of unilaterally 6-hydroxydopamine-lesioned rats, or on either the right or the left side of intact rats. Sham-lesioned controls received a superficial cortical cut at the same level. Seven days after surgery, apomorphine (0.25 mg/kg s.c.) was administered to 6-hydroxydopamine-lesioned animals and D-amphetamine (5 mg/kg i.p.) was administered to the non-dopamine-denervated ones. Two hours later, the animals were perfusion-fixed for the immunohistochemical detection of the nuclear protein Fos. A computerized image analysis technique was used to quantify, bilaterally, striatal Fos expression in 11 areas of the striatum. The frontocortical transection reduced both apomorphine- and amphetamine-induced Fos expression by 33-66% within the ipsilateral caudate-putamen. The effect was observed throughout the rostral portion of the striatal complex, where the lesioned cortical fibres terminate most densely. A separate batch of unilaterally 6-hydroxydopamine-lesioned rats were used to test the effect of frontocortical transection on amphetamine- and apomorphine-induced turning behaviour. Two groups of rats, showing similar rates of contralateral turning (7-8 turns/min) in response to apomorphine (0.25 mg/kg s.c.), were subjected to either a complete frontocortical transection or a sham lesion on the dopamine-denervated side. An additional two groups, showing comparable rates of ipsilateral turning (15 turns/min) in response to amphetamine (5 mg/kg i.p.), received similar lesions, but now on the side ipsilateral to the intact dopaminergic innervation.(ABSTRACT TRUNCATED AT 250 WORDS)
Cenci
M A
MA
Department of Medical Cell Research, University of Lund, Sweden.
Björklund
A
A
D000344:Afferent Pathways / Q000502:physiology; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology*; D003714:Denervation; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D016627:Oxidopamine / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013239:Stereotyped Behavior / Q000187:drug effects*
D016760:Proto-Oncogene Proteins c-fos; D016627:Oxidopamine; D000661:Amphetamine; D001058:Apomorphine