NATURAL SCIENCES

Journal of fundamental
and
applied researches

Influence of adrenergic regulatory mechanism blockade and stimulation on stress-induced changes of heart frequency and catalase activityof blood plasma in in-bred rats

2012. №4, pp. 77-87

Kuryanova Yevgeniya V. - Ph.D. (Biology), Associate Professor, Astrakhan State University, 1 Schaumyan Sq., Astrakhan, 414000, Russian Federation, fyzevk@rambler.ru

The study investigated the effect of blockading and stimulating аdrenergic regulatory mechanisms under two stress conditions: induced changes of heart frequency (HFr) and catalase activity of blood plasma. It covered the decrease of adrenergic influence on inbred male and female rats, modeled with the help of blockade peripheral ?1-adrenoreceptors (atenolol, 2 mg/kg b.w.) and blockade of catecholamine synthesis (alpha-methyl-tyrosine, 180 mg/kg b.w.). Amplification of adrenergic influences was created by stimulating the peripheral ?1-аdrenoreceptors (phenylephrine, 0,3 mg/kg b.w.) and blockading the return of capture mediators (amitriptyline, 2,5 mg / kg b.w.). The sharp emotional-painful stress duration of 1 hour caused the most significant HFr gain (up to 430–450 b/min, on 25–40 %, р^0,001) and catalase activity of blood plasma (up to 170–190 мccat/l, in 3,6–4,6 times, р^0,001) in rats with normal adrenergic mechanisms (the control group). The blockade of adrenergic mechanisms, it was found, sharply reduced the stress-induced growth of HFr and catalase activity of blood plasma. The effects of blockade ?1-adrenoreceptors are shown more strongly than the effects of a blockade of catecholamine synthesis. Stimulation of the adrenergic structures does not strengthen a stress-induced tachycardia, but modulates its stability (on a background of phenylephrine, the tachycardia weakens faster, while on a background of amitriptyline it remains very stable), and also reduces the stress-induced level of catalase activity of blood plasma in rats. In conclusion, increases in the HFr and catalase activity of blood plasma are characteristic displays of a stress reaction and depend on the condition of the adrenergic regulatory mechanisms.

Key words: ?1-adrenoreceptors blockade,?1-adrenoreceptors stimulation,catecholamine’s synthesis blockade,blockade of return capture mediators,sharp stress,heart frequency,catalase activity,inbred rats