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Identification and distribution of inositol trisphosphate receptor subtypes in catecholaminergic cell groups in rat brainstem and midbrain
Author(s) -
Kumar Natasha N,
Goodchild Ann K
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.889.2
Subject(s) - brainstem , catecholaminergic cell groups , midbrain , biology , inositol trisphosphate receptor , population , inositol , in situ hybridization , medicine , endocrinology , catecholaminergic , neuroscience , receptor , central nervous system , messenger rna , dopamine , biochemistry , environmental health , gene
Catecholaminergic (tyrosine hydroxylase immunoreactive, TH‐ir) cell groups in the brainstem are important gateways for regulating and setting blood pressure (BP), whilst those in the midbrain are involved in voluntary motor control, and diverse cognitive and behavioural functions. We have examined the distribution of inositol trisphosphate receptors subtype (IP3R1, IP3R2 and IP3R3) mRNA and protein expression in brainstem (A1, C1, A5) and midbrain (A8, A9, A10) cell groups. Digoxigenin‐labeled riboprobes encoding rat IP3R1‐3 were synthesized and validated by sequencing cDNA. Following anaesthesia and perfusion (4%PFA/0.1MPB) coronal brain sections (40 μm) of male Sprague Dawley rats were processed for in situ hybridization for IP3R1, IP3R2 and IP3R3 mRNA and immunohistochemistry (IHC) for IP3R1 and IP3R3 combined with IHC for TH‐ir. The main findings are about 30% of A8, A9, A10 cell groups contain IP3R1 (31% ± 4%, 28% ± 2% and 31% ± 1% neurons respectively, n=3) whereas IP3R1 was absent in all brainstem TH‐ir cell groups. IP3R2 was absent in all brain TH‐ir cell groups. IP3R3 mRNA was present in a subpopulation of A1, C1 and A5 neurons (3 ± 2%, 16 ± 6 % and 31 ± 8% respectively, n=3) as well as A8, A9 and A10 neurons (17%, 10% and 8% of TH‐ir neurons respectively, n=2) but IP3R3 protein was absent in all TH‐ir somata. Brainstem signaling systems using IP3R do not appear to play a major role in BP regulation, except IP3R3 in a small subpopulation. IP3R1 and IP3R3 potentially regulate the activity of a specific population of neurons controlling motor and cognitive function. Research funded by NHMRC (457068).