Neurochemical and electrophysiological evidence that 5‐HT4 receptors exert a state‐dependent facilitatory control in vivo on nigrostriatal, but not mesoaccumbal, dopaminergic function

• DOI: 10.1046/j.0953-816x.2000.01453.x
• Publication Date: 2003-03-06T14:38:13Z
• Authors: Guillaume Lucas; Vincenzo Di Matteo; Philippe De Deurw...; Grégory Porras; Raúl Martín‐Ruiz; Francesc Artigas; Ennio Esposito; Umberto Spampinato
• Keywords: Nigrostriatal pathway; Dorsal raphe nucleus; Raphe nuclei

Abstract In this study we investigated, using in vivo microdialysis and single unit recordings, the role of serotonin 4 (5‐HT ) receptors control nigrostriatal mesoaccumbal dopaminergic (DA) pathway activity. freely moving rats, 5‐HT antagonist GR 125487 (1 mg/kg, i.p.), without effect on its own, significantly reduced enhancement striatal DA outflow induced by 0.01 (−35%) 0.1 (−66%), but not 1 s.c. haloperidol (HAL). Intrastriatal infusion µ m had no influence basal outflow, attenuated (−49%) mg/kg HAL. Systemic administration modified neither nor HAL‐stimulated accumbal outflow. halothane‐anaesthetized or 10 125487, itself, failed to modify changes elicited electrical stimulation (300 µA, ms, 20 Hz, 15 min) dorsal raphe nucleus. Finally, (444 µg/kg, i.v.), whilst affecting firing neurons within either substantia nigra ventral tegmental area, (1–300 i.v.) impulse flow only. These results indicate that exert a facilitatory both release nigral neuron only when transmission is under activated conditions. Furthermore, they striatum constitutes major site for expression exerted release. contrast, have activity