Ganchev, T.

Negrev, N.

Zaharieva, R.

English

Varna Medical University Press: Journals

Scripta Scientifica Medico, vol 27 (1990), pp. 39-41 Copyright © Medicina i Fizkultura, Sofia ADRENERGIC INFLUENCES ON ERYTHROCYTE DEFORMABILITY IN RATS T. Ganchev, N. Negrev, R. Zaharieva Department of Physiology, Higher Institute of Medicine, Varna Key-words: Erythrocyte deformability - phenaxybenzarnine - isoprenaline - dobutamine -reserpine - salbutamol - rats It is known that erythrocyte deformability is one of their most important properties - to change their configuration when passing through the critical points of microcirculation [2]. The state of spectrin-actin system in erythrocyte membrane plays an important role in this aspect thus enabling the cell to adapt to the intensity of blood flow in the vascular bed. Loss of this property reduces their half-life "in vivo". It is indicated that spectrin really plays an essential role in the formation of covalent-bound parts of erythrocyte membrane. It is supposed that these regions of bilayers can move in the membrane structure and diminish its deformability [5]. A series of pharmacological agents change erythrocyte deformability such as adrenalin, isopr enalin, prostaglandins, pyracetam [4,9] under conditions "in vitro" and "in vivo" as well. The purpose of the present study is to follow-up these changes setting in this significant functional parameter of erythrocytes under "in vivo" conditions under the influence of adrenergic agents varying in their mechanism of action and influencing on the adrenergic neurone or on alpha- and beta-adrenoreceptors. We proceed mainly from two considerations: the lack of systemic literature data available on this topic, and, second, the established fact that stimulation of the adrenergic system has a positive reflection on erythropoiesis. Data obtained will enable us to throw certain light on the adrenergic dependence of this important property of the single erythrocyte influencing upon rheological peculiarities of circulating blood MATERIAL AND METHODS Our observation covered a total of 169 white male rats of Wistar breed with body weight of 170-180 g. There were 85 control and 84 experimental animals divided into 6 control and 6 experimental groups. Group one - treated with reserpine (R)-Fluka (Switzerland) in a dose of 2 mg/kg b.w. s.c. daily, control animals were injected vehicle only, group two - treated with phenoxybenzamine (РВА)-Koch-Light (England) in a dose of 5 mg/kg b.w. intraperitoneally daily, group three - injected with isoprenaUne (IP)-Koch-Light (England) twice in a dose of 5 mg/kg b.w. intraperitoneally; group four - treated with propranolol (PR)-ICI (England) twice in a dose of 5 mg/kg b.w. intraperitoneally, group five - treated with dobutamine (DB)-Lilly Res. (England) twice in a dose of 3 mg/kg b.w. s.c, and group six - treated with salbutamol (SB)-Polfa (Poland) in a dose of 5 mg/kg b.w. s.c. daily. Controls from the rest five groups were treated with physiological saline (PS). Experiment duration was 3 days for all groups. Erythrocyte deformability was estimated after the method of Tannert-Lux [12] in a modification of Zaharova et al. [2]. The essence of the method consists in the comparison of diameters of a spot from an isotonic buffer (Di) and of a spot from threefold washed-up erythrocyte suspension with hematocrit of 0,60 (D2) on filter paper Filtrak 390 (GDR). When erythrocyte spot diameter D2 is larger D1/D2 index will be smaller, i.e. there is an increased erythrocyte deformability. The smaller diameter of erythrocyte spot will increase this index what means a reduced deformability. Representative error of this method according to our data was delta = 0,017, i.e. an index of 3,35+ /-0,017. Results were processed by the methods of variation statistics by using of Student-Fisher's t-criterion. 40 Т. Ganchev, N. Negrcv, R. Zaharieva RESULTS AND DISCUSSION Erythrocyte deformability changes are presented on table 1. It is evident that erythrocyte deformability does not change in R-treated rats although postreserpine adrenergic blockade setting in as results from exhaustion of noradrenalin storages of impounding vesicles [10] suppresses erythropoiesis [1]. Despite the reduction of reticulocyte count and of 59-Fe incorporated into erythrocytes (indexes of inhibited bone-marrow erythropoiesis) it does not influence upon functional properties of the erythrocyte as a whole and on its membrane in particular. Table 1 Erythrocyte deformability Treatment n Erythrocyte deformability index Real difference in % I. Peserpine controls II. Phenoxybenzamine controls III. Isoprenaline controls IV. Propranolol controls V. Dobutamine controls VI. Salbutamol controls 15 15 14 15 10 10 15 15 15 15 15 15 3,06+\-0,Ю 3,07+\-0,06 3,78\-0,08 2,92+\-O,10 3,06+\-0,06 3,74+\-0,11 3,20+\-0,08 3,08+\-0,09 3,22+\-0,11 3,86+\-0,16 3,67+\-0,13 3,56+\-0,14 +0,32 -29,45 p<0,001 + 18,18 p<0,001 -3,90 + 16,58 p<0,01 -3,08 Data are presented as x -f /- Sx. Percentage difference is calculated towards controls. Sign ( + ) means increase, sign (-) - decrease, n is number of animals. Index increase means erythrocyte deformability reduction (see "Methods"). Non-selective alpha-adrenoceptor blockade by РВА reduces by 29,45 per cent (p< 0,001) erythrocyte deformability in comparison with that of controls. This finding is contrary to a certain extent to the increased reticulocyte number [7] as far as it is known that metabolically active cells possess better functional characteristics. It seems possible that deformability reduction is due not only to alpha-adrenergic receptor blockade and noradrenalin elevation but also to the extrareceptor РВА action proved concerning other systems [14]. It is known that adrenalin diminishes this erythrocyte property [4]. Analysis of data obtained after non-selective and selective influences on beta-adrenoceptors demonstrates that IP stimulates erythrocyte deformability by 18,18 per cent (p< 0,001) while PR (a non-selective beta-blocker) does not change significantly this function. This suggests a definite beta-adrenergic dependence of this functional erythrocytic property. The fact that treatment with DB, a betai-adrenoceptor stimulant, almost repeats IP effect confirms the idea of betai-adre­nergic dependence of the property of erythrocyte deformability. Precizing of an eventual beta2-Adrenergic influences on. 41 receptor participation in this erythrocyte function does not show such a dependence (table 1-VI). Stimulating effect of IP and DB on erythrocyte deformability is in accordance with rejuvenation of erythrocyte population (enhanced reticulocyte count)! 1J and contrary to data of other authors [4] obtained in an "in vitro" system in a dose of IP of 10" M. As far as it is known that erythrocyte deformability depends on age, metabolic cellular state and viscose-elastic properties of erythro­cyte membrane [3] our data are confirmed by the known facts concerning stimulation of cellular metabolic processes after treatment with IP and DB [6,11,13] Jt is probable that the presence of younger erythrocytes with enhanced metabolic processes as result from beta-adrenostimulation determines the changed into a positive direction erythrocyte deformability. We can conclude that suppression of functions of the neuronal link of the adrenergic mediator unit does not change erythrocyte deformability. This essential erythrocyte function depends on the functional state of receptor components of the adrenergic system: it is inhibited in case of alphal,2-adrenoceptor blockades which is probably due to noradrenalin enhancement, and it is elevated in case of betal-adrenostimulation which possibly depends on the stimulated cellular metabolism, too. The aforementioned changes should be considered with a view to their influence upon blood rheological properties especially when certain anomalies are present. REFERENCES 1. Ганчев, Т. Върху някои въпроси от адренергичната регулация на еритропоезата и плазмената еритропоетинова активност у плъхове. Канд. дис. Варна, ВМИ, 1975.-2. Захаром, Н.Б„ Н.И. Цилик, M.Л. Клячкнн. Лаб. дело, 1983,N 9, 3-6.- 3. Моисеева, О.И. Физиол. ж. СССР, 77, 1986,93-103.- 4. Allen, J.E., H.Rasmussen. Science, 174,1971,512-516.-5. Bull, B.S. Blood Cells, 13,1988,395-396.- 6. Byron, J.W. Experim. Hemaiol., 3,1975,44-53.- 7. Ganchev, Т.- In: Proc. Internal. Union Physiol. Sci.; 28. Internal. Congr. Budapest, 1980, XTV, Abstracts, p. 1499.- 8. Fisher, J.W., P.K. Nelson, B. Beckman, A.Burowski. In: Renal Endocrinology. M.J. Dunn, ed. Baltimore, Williams & Wilkins. (Москва, Медицина, 1987,196-241 - пер. на русс.)- 9. Gini, E.K., J . Sonnet. J . Clin. Pathol, 40,1987,99-102.-10. Longer, S.Z. Neurotransmitter systems and their clinical disorders. N.Legg, ed. Academic Press (Москва, Медицина, 1982,38-59 - пер.на русс.)-11. Nicolau, J., K.T. SassakL Gen. Pharmacol., 14,1983, 705-708.- 12. Tannert, C , W.Lux. Acta Biol Med Germ., 40, 1981, 739-742.- 13. Yoko, S., D. Hideijo. Jap. J. Pharmacol., 37,1985,21.2-14.-14. Zimmerman, B.G., J . Chia liao, J . Gisslen. /. Pharmacol Experim. Ther., 176,1971,603-610. АДРЕНЕРГИЧЕСКИЕ ВЛИЯНИЯ НА ЭРИТРОЦИТАРНУЮ ДЕФОРМАБИЛЬНОСТЬ У КРЫС Т. ГанчеВ, Н. НегреВ, Р. Захариева Р Е З Ю М Е Изучается влияние различных механизмов действия адренеергических агентов на эритроцитарную деформабильность в условиях "нн виво". Устанавливается, что блокада неврального звена адренергической медиаторной единицы резерпином не вызывает изменения зритроцитной деформабильности, в то время как феноксибензаммн, неселективныи альфа-адреноблокер, значительно ее понижает (29,45 %, р < 0,001). Неселективная бета-адренорецепторная стимуляция изопреналином повышает эритроцитную деформабильность на 18,18 % (р< 0,001), а блокада этих рецепторов пропранололом не приводит к существенным изменениям. Добутамин как бета 1«адрс норе цс игорный стимулянт повторяет стимулирующий эффект изопреналина. В заключение можно принять утверждение о том, что эритроцнтная деформабильность у крыс выявляет определенную зависимость от функционального состояния адренергических рецепторов и связанных с этим обменных процессов. Она заторможена при блокаде альфа 1,2-адренорецепторов и повышена при 6ета1-адреностимуляции. 

ADRENERGIC INFLUENCES ON ERYTHROCYTE DEFORMABILITY IN RATS

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ADRENERGIC INFLUENCES ON ERYTHROCYTE DEFORMABILITY IN RATS

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