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Role of spinal circuits in the rhythmic activity of sympathetic nerves innervating brown adipose tissue
Author(s) -
Madden Christopher J,
Morrison Shaun F
Publication year - 2006
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.20.4.a776-a
Subject(s) - microinjection , bicuculline , central pattern generator , spinal cord , serotonin , microinjections , 5 ht receptor , nmda receptor , neuroscience , chemistry , biology , endocrinology , medicine , anatomy , rhythm , antagonist , receptor
To determine whether brown adipose tissue (BAT) sympathetic nerve activity (SNA) displays characteristic burst frequencies and to characterize the role of spinal circuitry in this rhythmic activity, BAT SNA was increased in urethane/chloralose‐anesthetized rats (1) by microinjection of prostaglandin E2 (60ng/60nl) into the medial preoptic area, (2) by microinjection of NMDA (12 pmol/60nl) or bicuculline (30pmol/60nl) into the raphe pallidus, or (3) by microinjection of NMDA (12pmol/60nl) or serotonin (2nmol/60nl) into the intermediolateral cell column at the third thoracic segment (T3 IML). Microinjection of the excitatory amino acid (EAA) antagonist, kynurenate (6nmol/60nl), into the T3 IML prevented the T3 NMDA‐evoked activation, but potentiated the serotonin‐evoked activation of BAT SNA. All conditions resulted in similar power spectra of BAT SNA (peak power: 0.75‐2 Hz), the most prominent burst frequency range of BAT SNA. Transection of the spinal cord rostral to the spinal microinjections did not alter the dominant power frequencies of the spinally‐evoked responses. These results indicate that there is a rhythmic component of BAT SNA that can be evoked from the spinal cord. Furthermore the rhythmic component of BAT SNA does not require activation of EAA receptors within the IML and it can be generated in the absence of supraspinal input. Supported by: NIH grants DK065401 (CJM) and NS40987 (SFM).