ABSTRACT
<p><b>AIM</b>To investigate the role of overexpression of beta2-adrenoceptor on contraction in cardiac myocytes isolated from failure hearts of rats and primarily analyses its mechanisms.</p><p><b>METHODS</b>Primarily cultured cardiac myocytes were infected with adenovirus containing the sequence for human beta2-adrenoceptors. The expression of beta2-adrenoceptors was tested by Western blot. The contraction amplitudes induced by isoprenaline stimulation were measured.</p><p><b>RESULTS</b>Overexpression of beta2-adrenoceptor increased the content in failure cardiac myocytes. The contraction amplitudes in failure cardiac myocytes were lower than that in the control (P < 0.01). Overexpression of beta2 adrenoceptor improved the contraction of failure cardiac myocytes (P < 0.01, Failure+ Adv.Beta2 group vs. Failure group). Selective beta2-adrenoceptor antagonist ICI 118,551 partially reversed the effects (P < 0.05, Failure+ Adv.beta2 + ICI group vs Failure + Adv.beta2 group), but the contraction amplitudes in this Failure +/- Adv.beta2 + ICI 118,551 group were still higher than that in only heart failure group (P < 0.05). Selective beta1 adrenoceptor antagonist CGP20712A completely inhibited the effects of overexpression of beta2 adrenoceptor on contraction amplitude in failure cardiac myocytes.</p><p><b>CONCLUSION</b>Overexpression of beta2-adrenoceptors improves the contraction of cardiac myocytes isolated from failure hearts of rats. The effect is related to beta1-adrenoceptor.</p>