Tanaka E, Yamakawa A, Yamamura M, el Borai N, Ito K, Nakano S, Nakazawa H
Department of Physiology, Tokai University School of Medicine, Isehara, Japan.
Jpn J Physiol. 1995;45(6):1043-51. doi: 10.2170/jjphysiol.45.1043.
Previous studies in our laboratory demonstrated that microcalorimetry is an appropriate method for estimating the physiological function of isolated rat brown adipocytes. In the present study, to elucidate the mode of action of typical and atypical beta-adrenoceptors on heat production of this cell, the effect of novel adrenergic beta 3-agonists was compared with that of other typical adrenergic reagents by direct microcalorimetry. Isoproterenol and beta 3-agonists, BRL37344, ICI215001, and CGP12177, increased heat production in a dose-dependent manner, however, phenylephrine had no effect. Propranolol and pindolol did not increase the heat production but attenuated the effect of isoproterenol and BRL37344 in a dose-dependent manner. Molar IC50 values of propranolol and pindolol for BRL37344 were about 10(-5) and 3 x 10(-6) M, respectively, whereas those of the two antagonists for isoproterenol were about 3 x 10(-7)M. The pA2 values by Schild analysis of propranolol vs. isoproterenol and BRL37344 were 7.91 and 6.13, respectively. These results suggest that heat production may be regulated via both beta 3- and typical beta-adrenoceptors in brown adipocytes.
我们实验室之前的研究表明，微量热法是评估分离的大鼠棕色脂肪细胞生理功能的一种合适方法。在本研究中，为了阐明典型和非典型β-肾上腺素能受体对该细胞产热的作用方式，通过直接微量热法比较了新型肾上腺素能β3-激动剂与其他典型肾上腺素能试剂的作用效果。异丙肾上腺素和β3-激动剂BRL37344、ICI215001以及CGP12177均以剂量依赖性方式增加产热，然而，去氧肾上腺素没有作用。普萘洛尔和吲哚洛尔不会增加产热，但会以剂量依赖性方式减弱异丙肾上腺素和BRL37344的作用效果。普萘洛尔和吲哚洛尔对BRL37344的摩尔IC50值分别约为10^(-5) M和3×10^(-6) M，而这两种拮抗剂对异丙肾上腺素的摩尔IC50值约为3×10^(-7) M。通过Schild分析得出普萘洛尔对异丙肾上腺素和BRL37344的pA2值分别为7.91和6.13。这些结果表明，棕色脂肪细胞中的产热可能通过β3-肾上腺素能受体和典型β-肾上腺素能受体共同调节。
