Effects of Non-Opiate Analogue of Leu-Enkephalin on the Ion Currents, Number of Nucleoli, and p53 Expression in Isolated Cardiomyocytes of Albino Rats

Acute exposure of isolated ventricular cardiomyocytes to non-opiate analogue of leu-enkephalin (NALE peptide: Phe-D-Ala-Gly-Phe-Leu-Arg) in a concentration of 100 μg/liter and 6-h incubation in NALE solution did not significantly change ATP-dependent K+ current, L-type Ca2+ current, p53 protein expression, and number of nucleoli in the cardiomyocyte nuclei. Incubation of cardiomyocytes with NALE (100 μg/liter) in combination with NOP receptor blocker J-113397 (1 mg/liter) was followed by an increase in Ca2+ L-type current and the number of p53+ cells. The exposure of cardiomyocytes to NALE in a concentration 1000 μg/liter induced similar changes in the studied parameters (increase in Ca2+ L-type current and number of p53+ cardiomyocytes); an increase in the mean number of nucleoli was also observed. Our findings suggest that NALE peptide has direct effect on cardiomyocytes and NOP receptors are involved in this effect.

Evaluating Some Parameters Of Wistar Rat Brain In Traumatic Brain Injury Model With Administration Of Proline-Containing Peptides

Objective — To examine the morphometric parameters of neurons and the oxidative status of the Wistar rat brain tissues after administering proline-containing peptides, also known as glyprolines (Arg-Gly-Arg-Pro-Gly-Pro [RGRPGP] and Thr-Lys-Pro-Arg-Pro-Gly-Pro [WKPRPGP; Selank]), on a traumatic brain injury (TBI) model. Study subjects — Our study involved 26 mature male Wistar rats (2.5-3 mos. old, 220-300 g). The morphometric parameters of neurons and the oxidative status of animal brain tissues were studied. Material and Methods — Four experimental groups were formed. Group 1 included intact control animals. Animals in three other groups were subjected to TBI via free fall of a 50 g weight from a height of 50 cm on the second day of the experiment and received the following injections: 0.9% sodium chloride solution in Group 2; WKPRPGP peptide solution in Group 3; RGRPGP peptide solution in Group 4. Substances were administered intraperitoneally on a daily basis at a dose of 0.1 mg/kg from day 1 through day 5 of the experiment. Morphometric parameters of rat brain neurons were studied on paraffin sections stained with hematoxylin and eosin. The intensity of free radical processes in the brain tissue was investigated by chemiluminescence. Results — An analysis of morphometric parameters revealed significant increases in the neuronal cytoplasm area, nucleolar area, number of nucleoli, and nuclear-nucleolar index with the introduction of the RGRPGP peptide after TBI, compared with the WKPRPGP peptide under the same conditions. After TBI and peptide administration, we observed an oxidative stress in the neocortex of Wistar rats, and it was more pronounced in the group of animals treated with RGRPGP. Conclusion — After RGRPGP peptide administration, we observed an increase in the morphometric parameters of neurons in the closed TBI model: a larger area and a greater number of nucleoli. Chemiluminescence data implied that WKPRRPGP peptide better protected brain tissue in rats from the effects of oxidative stress caused by TBI.