Regulation of striatal dopamine release through 5-HT1 and 5-HT2 receptors

✍ Scribed by Ngan-Koon Ng; How-Sung Lee; Peter T.-H. Wong

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 173 KB
• Volume: 55
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(19990301)55:5<600::aid-jnr7>3.0.co;2-#

✦ Synopsis

Dopamine (DA) release in the striatum is regulated by 5-hydroxytryptamine (5-HT, serotonin) through putative heteroreceptors. However, the effect of 5-HT is controversial. The present study investigated the effects of different 5-HT receptor ligands on DA release in the rat striatum by using in vivo microdialysis in conscious and freely moving rats. Perfusion with 5-carboxamidotryptamine, anpirtoline, pindobind-5-HT 1A , and isamoltane demonstrated the involvement of 5-HT 1A and 5-HT 1B receptors in facilitating DA release. In contrast, 5-HT 2 receptors mediated inhibition of DA efflux, as shown by experiments with DOI [R-(؊)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane] and ketanserin. A 5-HT 3 agonist (1-(m-chlorophenyl)-biguanide hydrochloride) did not have any effect. None of the agonists used affected DA uptake into striatal synaptosomes. Unilateral 6-hydroxydopamine lesioning of the nigrostriatal DA pathway led to a selective decrease in 5-HT 2 receptors. It is concluded that there are 5-HT 2 heteroreceptors at the dopaminergic terminals that mediate inhibition of DA release. Further investigation is required to clarify the localization of the 5-HT 1 receptors in the striatum.