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Anatomical location and electrophysiological properties of the serotonin receptors type 2 (5‐HTR2) in the nucleus of the solitary tract (nTS).
Author(s) -
Austgen James R,
Dantzler Heather A,
Kline David D
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.1011.8
Subject(s) - electrophysiology , excitatory postsynaptic potential , solitary tract , agonist , patch clamp , neuroscience , chemistry , serotonin , synaptophysin , postsynaptic potential , medicine , endocrinology , biology , receptor , nucleus , inhibitory postsynaptic potential , immunohistochemistry
Serotonin plays a major role in cardiorespiratory function in health and disease. While 5‐HTR2 is believed to be excitatory, its location, function and mechanism of action in the nTS requires clarification. We determined the location and electrophysiological properties of 5‐HT and 5‐HT2R subtypes in the nTS. In immunohistochemical studies, nTS sections where treated with antibodies against 5‐HTR2A, ‐2B and ‐2C. The synaptic vesicle marker synaptophysin was used to identify synaptic terminals. nTS neurons were recorded using the patch clamp technique in the slice preparation. Spontaneous and solitary tract‐evoked excitatory postsynaptic currents (s/eEPSC) and current‐induced action potential discharges (APD) were recorded. 5‐HT2 receptor subtypes displayed distinct immunoreactivity: 5‐HTR2A in fibers and cell bodies; 5‐HTR2B in the cell soma; 5‐HTR2C in fiber‐like processes. A fraction of 5‐HT2C immunoreactivity co‐labeled with synaptophysin. Electrophysiological recordings of nTS neurons showed an increase in the frequency of sEPSCs with 5‐HT (10 μm, 15.3 ± 2.5 vs. 47.1 ± 8.3 Hz, p<0.05). α‐methyl 5‐HT (a general R2 agonist, 10 μm) decreased the amplitude of sEPSC (‐21.9 ± 1.2 vs. ‐14.9 ± 0.8 pA). Application of a 2B agonist (BW 723C86, 10μm) reduced current injected‐APD. This information suggests that 5‐HTR2 subtypes are located in the NTS and have a roll in synaptic function. HL085108 (DDK)