title: Evidence of D2 receptor expression in the nucleus incertus of the rat.
abstract: The nucleus incertus (NI), located in the caudal brainstem, mainly consists of GABAergic neurons with widespread projections across the brain. It is the chief source of relaxin-3 in the mammalian brain and densely expresses corticotropin-releasing factor type 1 (CRF1) receptors. Several other neurotransmitters, peptides and receptors are reportedly expressed in the NI. In the present investigation, we show the expression of dopamine type-2 (D2) receptors in the NI by reverse transcriptase-polymerase chain reaction (RT-PCR), western blotting (WB) and immunofluorescence (IF). RT-PCR did not show expression of D3 receptors. D2 receptor short isoform (D2S)-like, relaxin-3, CRF1/2 receptor and NeuN immunoreactivity were co-expressed in the cells of the NI. Behavioural effects of D2 receptor activation by intra-NI infusion of quinpirole (a D2/D3 agonist) were evaluated. Hypolocomotion was observed in home cage monitoring system (LABORAS) and novel environment-induced suppression of feeding behavioural paradigms. Thus the D2 receptors expressed in the NI are likely to play a role in locomotion. Based on its strong bidirectional connections to the median raphe and interpeduncular nuclei, the NI was predicted to play a role in modulating behavioural activity and the present results lend support to this hypothesis. This is the first evidence of expression of a catecholamine receptor, D2-like immunoreactivity, in the NI.
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore.
authors: Jigna Rajesh
authors: JR
authors: Kumar
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
authors: Ramamoorthy
authors: R
authors: Rajkumar
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
authors: Usman
authors: U
authors: Farooq
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
authors: Liying Corinne
authors: LC
authors: Lee
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
authors: Francis Chee Kuan
authors: FC
authors: Tan
authors: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore. Electronic address: gavin_dawe@nuhs.edu.sg.
authors: Gavin S
authors: GS
authors: Dawe
mesh_terms: D056044:Actigraphy; D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism; D015153:Blotting, Western; D018491:Dopamine Agonists / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006799:Housing, Animal; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019257:Quinpirole / Q000494:pharmacology; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000819:agonists / Q000378:metabolism; D012065:Relaxin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D034961:Antigens, Nuclear; C000607792:DRD2 protein, rat; D018491:Dopamine Agonists; C493595:Drd3 protein, rat; D009419:Nerve Tissue Proteins; C466742:RLN3 protein, rat; C546339:Rbfox3 protein, rat; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D019257:Quinpirole; D012065:Relaxin
keywords: D(2) receptors; Dopamine; Locomotion; Nucleus incertus; Quinpirole; Relaxin-3