I I Meskhishvili

Publications of I I Meskhishvili

• Effects of low ethanol doses on heart rhythm in rabbits.

  Authors: K Sh Nadareishvili, I I Meskhishvili, D D Kakhiani, G L Ormrtsadze, M T Khvedelidze, E T Chitanava

  Bulletin of experimental biology and medicine. 10/2004; 138(3):271-5.

  Effects of low ethanol doses on the vagosympathetic mechanisms of heart rhythm regulation were studied in rabbits. Analysis of heart rhythm variability showed that single intragastric administrationEffects of low ethanol doses on the vagosympathetic mechanisms of heart rhythm regulation were studied in rabbits. Analysis of heart rhythm variability showed that single intragastric administration of 0.5 mg/kg ethanol caused tachycardia in animals with initial predominance of vagal activity and bradycardia in animals with predominating sympathetic mechanisms. This was associated with general activation of all regulatory effects on the heart rhythm and a drastic increase in power spectrum for all frequency ranges, though with a certain deficiency of vagal effects. However, after 24 h the vagal component of the spectrum drastically increased in animals of both groups, while other parameters did not differ from the control. Presumably, this rebound can be used as a physiological marker, ethanol tolerance measure, formation of the abstinence syndrome and liability to alcoholism.

• Heart rate variability in Chinchilla rabbits.

  Authors: K Sh Nadareishvili, I I Meskhishvili, D D Kakhiani, G L Ormotsadze, G T Nazarishvili, M G Gvasalia, M T Khvedelidze, V Ya Sandodze

  Bulletin of experimental biology and medicine. 01/2003; 134(6):568-70.

  Temporal and spectral parameters of heart rate variability were studied as criteria for classification of mature Chinchilla rabbit population according to their basal neurovegetative status. TheTemporal and spectral parameters of heart rate variability were studied as criteria for classification of mature Chinchilla rabbit population according to their basal neurovegetative status. The absolute values of total spectral power density and individual frequency bands differed significantly in vagotonics and sympathotonics. However, standardized spectral power distributions in high-, low- and very low-frequency ranges were similar in both groups. Our results suggest that the intensity of regulatory influences on the heart at all levels of regulation, which can be evaluated by spectral analysis, is similarly distributed in both groups. Hence, the observed differences in the heart rate variability can not be explained by peculiarities in sympathovagal balance, but are determined by more universal mechanisms.

• [Initial heart rate variability and radiosensitivity in rabbits]

  Authors: K Sh Nadareishvili, I I Meskhishvili, D K Nadareishvili, G L Ormotsadze, M M Nikolaishvili, G S Iordanishvili, V Ia Sandodze, E G Chitanava

  Radiatsionnaia biologiia, radioecologiia / Rossiĭskaia akademiia nauk. 45(2):133-44.

  The goal of the work was to investigate the rabbits' radiosensitivity dependence on the initial functional state of the autonomous nervous system (ANS), as assessed by time-frequency parameters ofThe goal of the work was to investigate the rabbits' radiosensitivity dependence on the initial functional state of the autonomous nervous system (ANS), as assessed by time-frequency parameters of the heart rate variability (HRV). Survival rate and rhythm-cardiologic correlates of the pathological processes following total X-irradiation, at doses of 2 and 12 Gy, were studied with an aid of modern computer technologies of measurement and data analysis. It has been found that the animals with initial prevailing of adrenergic influences on the HRV ("sympathicotonics") are significantly more sensitive to irradiation than those in which the parasympathetic prevalence was evident ("vagotonics"). The most characteristic and determining difference between these two groups of animals is initial level of the sum regulatory influences on the heart rhythm, which is manifested in value of total power of spectral density (TP) of HRV. In the sympathicotonics the TP is significantly lower than in the vagotonics. The primary HRV response to irradiation practically does not differ according to the dose and manifests in sharp suppression of the TP in both groups of the animals. At 12 Gy this process is irreversible. In the sympathicotonics it develops earlier and terminates with death much sooner than in the vagotonics. An average life-span of the rabbits, at this dose, is 18.8 +/- 2.6 days in vagotonics, and 10.3 +/- 1.3 days in sympathicotonics (p < 0.02). At 2 Gy initial sharp decrease of the TP in the vagotonics lasts one week only. Then the sum regulatory influence of the ANS on the heart rate increases (rebound) and this condition, which probably points at general resistance of the organism, could be seen within two months; at the end of third month it stabilizes at the initial level. In the sympathycotonics initial sharp decrease of the TP also occurred, however no rebound was observed. The results obtained show that low initial level of the TP of HRV is sufficiently correct marker for higher radiosensitivity in the sympathotonic rabbits against the vagotonic ones.