Epinephrine enhances the sensitivity of rat vagal chemosensitive neurons: Role of β3-adrenoceptor

Qihai Gu, You Shuei Lin, Lu Yuan Lee

研究成果: 雜誌貢獻文章同行評審

17 引文 斯高帕斯(Scopus)

摘要

This study was carried out to determine whether epinephrine alters the sensitivity of rat vagal sensory neurons. In anesthetized rats, inhalation of epinephrine aerosol (1 and 5 mg/ml, 3 min) induced an elevated baseline activity of pulmonary C fibers and enhanced their responses to lung inflation (20 cmH2O, 10 s) and right atrial injection of capsaicin (0.5 μg/kg). In isolated rat nodose and jugular ganglion neurons, perfusion of epinephrine (3 μM, 5 min) alone did not produce any detectable change of the intracellular Ca2+ concentration. However, immediately after the pretreatment with epinephrine, the Ca2+ transients evoked by chemical stimulants (capsaicin, KCl, and ATP) were markedly potentiated; for example, capsaicin (50 nM, 15 s)-evoked Ca2+ transient was increased by 106% after epinephrine (P < 0.05; n = 11). The effect of epinephrine was mimicked by either BRL 37344 (5 μM, 5 min) or ICI 215,001 (5 μM, 5 min), two selective β3-adrenoceptor agonists, and blocked by SR 59230A (5 μM, 10 min), a selective β3-adrenoceptor antagonist, whereas pretreatment with phenylephrine (α1-adenoceptor agonist), guanabenz (α2-adrenoceptor agonist), dobutamine (β1-adrenoceptor agonist), or salbutamol (β2- adrenoceptor agonist) had no significant effect on capsaicin-evoked Ca 2+ transient. Furthermore, pretreatment with SQ 22536 (100-300 μM, 15 min), an adenylate cyclase inhibitor, and H89 (3 μM, 15 min), a PKA inhibitor, completely abolished the potentiating effect of epinephrine. Our results suggest that epinephrine enhances the excitability of rat vagal chemosensitive neurons. This sensitizing effect of epinephrine is likely mediated through the activation of β3-adrenoceptor and intracellular cAMP-PKA signaling cascade.

原文英語
頁(從 - 到)1545-1555
頁數11
期刊Journal of Applied Physiology
102
發行號4
DOIs
出版狀態已發佈 - 四月 2007
對外發佈

ASJC Scopus subject areas

  • 生理學
  • 生理學(醫學)

指紋

深入研究「Epinephrine enhances the sensitivity of rat vagal chemosensitive neurons: Role of β<sub>3</sub>-adrenoceptor」主題。共同形成了獨特的指紋。

引用此