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Fenfluramine‐induced increase in preproenkephalin mRNA levels in the striatum: Interaction between the serotonergic, glutamatergic, and dopaminergic systems
Author(s) -
Liste Isabel,
Muñoz Ana,
Guerra Maria Jose,
LabandeiraGarcia Jose Luis
Publication year - 2000
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(20000301)35:3<182::aid-syn3>3.0.co;2-t
Subject(s) - serotonergic , dopaminergic , striatum , medicine , endocrinology , chemistry , sch 23390 , dopamine , fenfluramine , glutamatergic , ritanserin , pharmacology , glutamate receptor , serotonin , receptor
Fenfluramine (FE) is a halogenated amphetamine derivative that has been used in the treatment of obesity. It has been suggested that the effects of FE on the striatum are mediated by serotonergic mechanisms. However, several major afferent systems may be involved, and administration of FE may be useful to study interactions between these systems. In this work, the effects of FE on striatopallidal neurons and the possible involvement of the major striatal afferent systems were studied in rats by determination of FE‐induced changes in striatal levels of preproenkephalin (PPE) mRNA using in situ hybridization. Injection of FE induced a significant increase (60%) in striatal levels of PPE mRNA. This increase was blocked by pretreatment with the D 1 dopamine receptor antagonist SCH‐23390 or with the NMDA glutamate receptor antagonist MK‐801, or by lesion of the serotonergic system with 5,7‐dihydroxytryptamine or p‐chlorophenylalanine. In 6‐hydroxydopamine lesioned rats, the lesion‐induced increase in PPE mRNA levels was not affected by injection of FE, but was reduced by simultaneous serotonergic deafferentation. The results suggest that the serotonergic, glutamatergic, and dopaminergic system interact to increase striatal PPE mRNA levels after FE administration. Synapse 35:182–191, 2000. © 2000 Wiley‐Liss, Inc.