title: Neuropeptide Y-containing interneurons in the hippocampus receive synaptic input from median raphe and GABAergic septal afferents.
abstract: Neuropeptide Y has been extensively studied in the central nervous system due to a possible involvement of neuropeptide Y-containing neurons in cognitive functions. In the hippocampus neuropeptide Y is present in a subpopulation of nonpyramidal cells, which control the firing of hippocampal output neurons. In the present study we examined whether septohippocampal and raphe-hippocampal afferents--known to have a powerful effect on hippocampal electrical activity patterns--innervate neuropeptide Y-containing neurons in the hippocampal formation of the rat. Using a combination of pre- and postembedding immunostaining and tracing with Phaseolus vulgaris leucoagglutinin (PHAL) we showed that GABAergic afferents arising from the medial septal area extensively innervate neuropeptide Y-containing neurons. Afferents of median raphe origin, most of which are thought to be serotonergic, were also found to make multiple synaptic contacts with these cells. Thus, the neuropeptide Y-containing subpopulation of interneurons--which innervate distal dendrites of principal cells--are also among those through which different subcortical nuclei modulate information processing in the hippocampal formation.
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.
authors.forename: R
authors.initials: R
authors.lastname: Miettinen
authors.forename: T F
authors.initials: TF
authors.lastname: Freund
mesh_terms: D000344:Afferent Pathways / Q000737:chemistry / Q000502:physiology; D000818:Animals; D001931:Brain Mapping; D006624:Hippocampus / Q000737:chemistry / Q000502:physiology*; D007395:Interneurons / Q000737:chemistry / Q000502:physiology*; D008297:Male; D008845:Microinjections; D009478:Neuropeptide Y / Q000032:analysis / Q000502:physiology*; D010835:Phytohemagglutinins; D011903:Raphe Nuclei / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012688:Septum Pellucidum / Q000737:chemistry / Q000502:physiology*; D013569:Synapses / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D009478:Neuropeptide Y; D010835:Phytohemagglutinins; C100156:leukoagglutinins, plants