The following study examined the impact of IL-2 on Ca channel activity in the event of several hours' incubation in IL-2. The right ventricle free wall for action potential measurements was isolated and perfused with Tyrode solution. The whole-cell voltage clamp experiments were performed on enzymatically isolated single cardiomyocytes. The whole-cell voltage clamp recording of Ca currents was performed using the Cs-based pipette and bath solutions. The protocol with depolarizing prepulse (- 40 mV) was used to inactivate both Na current and Ca T-type current. The L-type Ca current was elicited by a series of 250 ms depolarizing square pulses with 10 mV increments. At the 15th minute of continuous recording, the peak density at 0 mV was - 3.036 ± 0.3015 pA/pF under IL-2 and - 3.008 ± 0.3452 pA/pF in control conditions. The IL-2 in moderate concentration (1 ng/mL) has no acute effects on I in rat ventricular cells. In contrast, to the lack of acute effects, the long-term incubation with IL-2 (2 h or more) produced a prominent enhancement of Ca L-type current. In rat, ventricular myocardium IL-2 (1 ng/mL) produced a very gradual prolongation of subendocardial APs which reached a maximal extent after 3-4 h of treatment. The patch clamp study shows an IL-2-induced I current activation, while the action potential studies on multicellular ventricular preparations suggest an IL-2-induced L-type Ca channel participation in the development of AP.

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Effect of successive administration vancomycin and amikacin in therapeutic doses on immature auditory organ was compared to single administration of the same drugs in chronic experiments on immature rabbits by recording of short-latency auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Drug administration always increased significantly the ABR peak I threshold. Ototoxic antibiotics did not change DPOAE, but selectively affected activity of outer hair cells. No enhancement of the ototoxic effects was observed after successive administration of the two antibiotics.

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