Abstract

ALFONSO, C; LAMANNA, V; RODRIGUEZ, M  and  PEREZ-GONZALEZ, M. Efecto de distintas maniobras Inotrópicas sobre la potenciación Post-Reposo en Aurícula Izquierda aislada de ratas. RFM [online]. 2002, vol.25, n.1, pp.59-62. ISSN 0798-0469.

Post-rest potentiation (PRP) was studied in rat left atria superfusal with tyrode solution, at 35°, bubbled with 95%O₂ :5%CO₂. The basic stimulation (1HZ) was interrupted for 2,4,8,16,32,64 and 128 seconds. A curve of potentiation as a function of rest interval (RI) was obtained. The contraction increase with the RI up to 32 sec and then a platean was reached. Increasing [Ca²⁺]e, from 1,7 to 3,4 mM, did not change this kinetics. Decreasing [Ca²⁺]e, 0,85mM, decreased the basal cotraction(BC) but PPR was mantained. Lowering [Na⁺]e, from 145 to 55 MM, increased BC and inhibited PRP. Cd²⁺ (0,02mM) and Ni²⁺ (0,2) deminished BC whitout changing PRP. Adding Mn²⁺ (0,2mM) was only experimental monover causing a change in the PRP kinetics: Thecontraction increased up to a 128 sec rest whitout reaching steady state. Conclussions: PRP depends on the Ca into the sarcoplasmic reticulum (SR). Its kinetics only Changed when Mn was added, suggesting that this substance may alter the Ca²⁺ movement inside the SR.

Keywords : Post-rest potentation; Atria; Rat.