Differential effects of kainic acid on dopamine and serotonin metabolism in ventral and dorsal striatal regions.
The comparative effects of kainic acid (KA) on dopamine (DA) and serotonin (5-HT) metabolism in ventral and dorsal striatum were investigated. Local injection of KA into the caudate-putamen (CP) increased by 155% DOPAC (2,3-dihydrophenylacetic acid), by 114% HVA (homovanillic acid) and by 79% 5-HIAA (5-hydroxyindoleacetic acid) concentrations; with little or no effect on monoamine levels. The (DOPAC + HVA)/DA ratio increased from 0.33 +/- 0.2 in vehicle-treated to 0.77 +/- 0.1 in KA-treated CP. 5-HIAA/5-HT ratio increased from 2.7 +/- 0.2 to 5.9 +/- 0.1 after KA treatment. However, direct KA injections into the olfactory tubercle (OT), the most ventral part of the ventral striatum, did not alter significantly the levels of DA, 5-HT, DOPAC, HVA or 5-HIAA. Since KA is a neurotoxin which preferentially destroys perykaria and dendrites, leaving unchanged terminal boutons and axons of passage, the lack of effects on DA and 5-HT metabolism in OT suggests, that contrary to the CP, interneurons and projecting neurons in the OT play no role in inhibitory feedback mechanisms to control DA and 5-HT activities.
Guevara
B H
BH
Department of Pharmacology, School of Pharmacy, Central University of Venezuela, Carácas.
Hoffmann
I S
IS
Cubeddu
L X
LX
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D006719:Homovanillic Acid / Q000378:metabolism; D007608:Kainic Acid / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D009830:Olfactory Bulb / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013238:Stereotaxic Techniques
D018690:Excitatory Amino Acid Agonists; D015102:3,4-Dihydroxyphenylacetic Acid; D012701:Serotonin; D007608:Kainic Acid; D004298:Dopamine; D006719:Homovanillic Acid