Extracellular serotonin changes in VLM during muscle contraction:: effects of 5-HT1A-receptor activation

被引:17
作者
Asmundsson, G
Caringi, D
Mokler, DJ
Kobayashi, T
Ishide, T
Ally, A
机构
[1] Univ New England, Coll Osteopath Med, Dept Pharmacol, Biddeford, ME 04005 USA
[2] Univ New England, Coll Osteopath Med, Dept Biochem, Biddeford, ME 04005 USA
[3] Tokyo Univ Mercantile Marine, Hlth Sci Ctr, Tokyo 135, Japan
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 1997年 / 273卷 / 06期
关键词
arterial blood pressure; heart rate; exercise pressor reflex; rostral ventrolateral medulla; caudal ventrolateral medulla; rat;
D O I
10.1152/ajpheart.1997.273.6.H2899
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
This study determined whether muscle contraction causes an increase in extracellular levels of serotonin (5-HT) in the rostral (rVLM) or caudal ventrolateral medulla (cVLM) in anesthetized rats. Muscle contraction, evoked by tibial nerve stimulation, increased mean arterial blood pressure (MAP) by 27 +/- 4 mmHg (n = 8). In addition, 5-HT levels in the rVLM were elevated by 65 +/- 9% during the contraction (n = 8). Results were similar over two repeated contractions. In contrast, muscle contraction increased MAP, but not 5-HT, levels in the cVLM (n = 6). Tibial nerve stimulation after muscle paralysis had no effect on either MAP or 5-HT levels in both rVLM and cVLM. Microdialysis of a 5-HT1A agonist, 8-OH-DPAT (10 mM), into the rVLM for 30 min (n = 6) blunted the MAP change and reduced 5-HT release during contraction. Administration of NAN-190, a 5-HT1A antagonist, into the rVLM had no effect on 5-HT release and cardiovascular responses during muscle contraction and blocked the changes in 5-HT, MAP, and heart rate to static contraction after subsequent microdialysis of 8-OH-DPAT. Results demonstrate that 5-HT levels in the rVLM increase during muscle contraction and that 5-HT1A-receptor activation in the rVLM blunts MAP response to muscle contraction via a decrease in the extracellular concentration of 5-HT.
引用
收藏
页码:H2899 / H2909
页数:11
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