Grignolo A, Light K C, Obrist P A
Pharmacol Biochem Behav. 1981 Mar;14(3):313-9. doi: 10.1016/0091-3057(81)90396-8.
The role of beta-adrenergic receptors in the mediation of the cardiodynamic effects of a shock-avoidance task was evaluated in conscious dogs with the cardioselective beta-adrenergic antagonist practolol. The animals were chronically instrumented for the measurement of peak rate of change of left ventricular pressure (LV dP/dt), heart rate (HR), cardiac output (CO), systolic (SPB) and diastolic (DBP) blood pressure and total peripheral resistance (TPR), and were each subjected to brief bouts of shock-avoidance with and without practolol pretreatment (2-4 mg/kg). Shock-avoidance evoked reliable increases of LV dP/dt, HR, CO, SBP and DBP, and decreases of TPR. Beta-adrenergic blockade virtually eliminated LV dP/dt increases, attenuated HR and CO increase as well as the vasodilatation, diminished SBP increases in certain animals but did not affect DBP increases. Stable interindividual differences in the magnitude of LV dP/dt and HR increases during shock-avoidance were demonstrated; these differences were abolished by beta blockade. These findings indicate that a beta-adrenergic mechanism accounted for most of the rise of LV dP/dt during avoidance but contributed proportionally less to the elevations of HR and CO. Inter-individual differences in myocardial reactivity were however completely ascribable to beta-adrenergic factors.
在清醒犬中，使用心脏选择性β-肾上腺素能拮抗剂心得宁，评估β-肾上腺素能受体在逃避电击任务的心脏动力学效应介导中的作用。动物长期植入仪器，用于测量左心室压力变化率峰值（LV dP/dt）、心率（HR）、心输出量（CO）、收缩压（SPB）和舒张压（DBP）以及总外周阻力（TPR），并且在有和没有心得宁预处理（2 - 4mg/kg）的情况下，对每只动物进行短暂的逃避电击试验。逃避电击引起LV dP/dt、HR、CO、SBP和DBP可靠增加，TPR降低。β-肾上腺素能阻断几乎消除了LV dP/dt的增加，减弱了HR和CO的增加以及血管舒张，减少了某些动物的SBP增加，但不影响DBP增加。在逃避电击期间，LV dP/dt和HR增加幅度存在稳定的个体间差异；这些差异被β阻断消除。这些发现表明，β-肾上腺素能机制在逃避期间占LV dP/dt升高的大部分原因，但对HR和CO升高的贡献比例较小。然而，个体间心肌反应性的差异完全归因于β-肾上腺素能因素。
