title: Neuronal responses to 5-hydroxytryptamine and dorsal raphe stimulation within the globus pallidus of the rat.
abstract: The projection from the dorsal raphe nucleus (DRN) to the globus pallidus (GP) was investigated electrophysiologically, in the urethane-anesthetized rat together with the responsiveness of cells in the GP to 5-hydroxytryptamine (5-HT) and noradrenaline (NA). The majority of spontaneously active cells in the GP had high regular firing rates. They were unaffected by both DRN stimulation (69/83 cells) and iontophoretically applied 5-HT (38/63 units) or NA (30/42 units) but were inhibited by GABA. A few cells (N = 10) were recorded from, that were spontaneously active but with a much lower and less regular firing rate, which, however, seemed to be much more responsive to 5-HT. In addition, DL-homocysteic acid (DLH) was used to activate silent cells and all seven cells activated in this manner were inhibited by 5-HT. In addition 5/6 cells that had their firings maintained by DLH were inhibited by stimulation of the dorsal raphe. The results show a lack of responsiveness to both 5-HT and DRN stimulation of the typically regular spontaneously active pallidal neurons. There seems to be a small population of normally quiescent cells, however, that is sensitive to 5-HT and receives an input from the DRN.
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D004558:Electric Stimulation; D005917:Globus Pallidus / Q000166:cytology / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D009435:Synaptic Transmission
chemical_list: D012701:Serotonin; D009638:Norepinephrine