Kaloyianni M, Rasidaki A
Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Zoology, Greece.
J Exp Zool. 1996 Oct 15;276(3):175-85. doi: 10.1002/(SICI)1097-010X(19961015)276:3<175::AID-JEZ1>3.0.CO;2-K.
We studied the effects of beta-adrenergic stimulation on the formation of adenosine 3', 5'-cyclic monophosphate (cAMP) and on the cell volume in Rana ridibunda red blood cells under O2 (high oxygen atmosphere) and under N2 (hypoxia) gases. Adrenergic stimulation caused the accumulation of cAMP and the swelling of R. ridibunda erythrocytes. 10(-5) M adrenaline and 10(-5) M isoproterenol seem to be the more efficient concentration in causing greater cell swelling. The amount of cAMP required for adrenergic swelling was minimal; swelling was observed at cAMP concentrations higher than 20 nM. Maximal swelling was seen when the cellular cAMP concentration reached 40 nM at high oxygen atmosphere. Isoproterenol caused a greater increase in water content than adrenaline. At hypoxic conditions the water content and cAMP concentrations obtained after stimulation with adrenaline and isoproterenol were greater than at high oxygen atmosphere. Since the adrenergic response seems to be blocked both by prazosin and propranolole the adrenoreceptors of R. ridibunda red cells may be classified as alpha 1- and beta-receptors. The enhancement of cAMP and cell swelling may be either due to an increase in the number of adrenoreceptors, or to increased responsiveness of the erythrocyte Na(+)-H+ antiporter to catecholamines during hypoxia. These responses are believed to enhance blood oxygen transport during periods of increased oxygen demands.
我们研究了β-肾上腺素能刺激对食用蛙红细胞在O₂（高氧环境）和N₂（低氧环境）气体条件下3',5'-环磷酸腺苷（cAMP）形成及细胞体积的影响。肾上腺素能刺激导致cAMP积累以及食用蛙红细胞肿胀。10⁻⁵ M肾上腺素和10⁻⁵ M异丙肾上腺素似乎是导致更大细胞肿胀的更有效浓度。肾上腺素能肿胀所需的cAMP量极少；在高于20 nM的cAMP浓度下观察到细胞肿胀。在高氧环境下，当细胞内cAMP浓度达到40 nM时出现最大肿胀。异丙肾上腺素比肾上腺素导致的水分含量增加更多。在低氧条件下，用肾上腺素和异丙肾上腺素刺激后获得的水分含量和cAMP浓度高于高氧环境。由于哌唑嗪和普萘洛尔似乎都能阻断肾上腺素能反应，食用蛙红细胞的肾上腺素受体可能可分为α₁受体和β受体。cAMP增加和细胞肿胀可能是由于肾上腺素受体数量增加，或者是由于低氧期间红细胞钠氢反向转运体对儿茶酚胺的反应性增强。据信这些反应在氧气需求增加期间可增强血液氧运输。
