title: Evidence for the differential co-localization of neurokinin-1 receptors with 5-HT receptor subtypes in rat forebrain.
abstract: Studies suggest that like selective 5-hydroxytryptamine (5-HT; serotonin) reuptake inhibitors, antagonists at neurokinin-1 receptors (NK(1)Rs) may have antidepressant and anxiolytic properties. NK(1)Rs are present in 5-HT innervated forebrain regions which may provide a common point of interaction between these two transmitter systems. This study aimed to investigate for cellular co-localization between NK(1)Rs and 5-HT receptor subtypes in mood-related brain regions in the rat forebrain. With experiments using fluorescence immunocytochemistry, double-labelling methods demonstrated a high degree of co-localization between NK(1)Rs and 5-HT(1A) receptors in most regions examined. Co-localization was highest in the medial septum (88% NK(1)R expressing cells were 5-HT(1A) receptor-positive) and hippocampal regions (e.g. dentate gyrus, 65%), followed by the lateral/basolateral amygdala (35%) and medial prefrontal cortex (31%). In contrast, co-localization between NK(1)Rs and 5-HT(2A) receptors was infrequent (< 8%) in most areas examined except for the hippocampus (e.g. CA3, 43%). Overall co-localization between NK(1)Rs and 5-HT(1A) receptors was much greater than that between NK(1)Rs and 5-HT(2A) receptors. Thus, these experiments demonstrate a high degree of co-localization between NK(1)Rs and 5-HT(1A) receptors in cortical and limbic regions of the rat forebrain. These findings suggest a novel site of interaction between NK(1)R antagonists and the 5-HT system.
authors: Department of Pharmacology, University of Oxford, Oxford, UK. sepehr.hafizi@cpft.nhs.uk
authors: Sepehr
authors: S
authors: Hafizi
authors: Florence
authors: F
authors: Serres
authors: Qi
authors: Q
authors: Pei
authors: Susan
authors: S
authors: Totterdell
authors: Trevor
authors: T
authors: Sharp
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D016548:Prosencephalon / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044282:Receptor, Serotonin, 5-HT1A / Q000032:analysis*; D044402:Receptor, Serotonin, 5-HT2A / Q000032:analysis*; D018040:Receptors, Neurokinin-1 / Q000032:analysis*
chemical_list: D044402:Receptor, Serotonin, 5-HT2A; D018040:Receptors, Neurokinin-1; D044282:Receptor, Serotonin, 5-HT1A