TY - JOUR
T1 - Age-related differences in the β-adrenergic vasodilator response in rat aortic rings
AU - Castillo-Hernandez, Maria Del Carmen
AU - Meraz-Cruz, Noemi
AU - Guevara-Balcazar, Gustavo
AU - Lopez-Canales, Jorge
AU - Lopez-Canales, Oscar
AU - Galindo, Norma
AU - Castillo-Henkel, Carlos
PY - 2010
Y1 - 2010
N2 - Mechanisms underlying age-dependent changes in vasodilator responses to β-adrenergic drugs are poorly understood. The aim of the current study was to compare responses to isoproterenol (a non-selective β-adrenergic receptor agonist) in phenylephrine or KCl precontracted aortic rings from 3 week and 3 month old male Wistar rats. Both the mechanism and the subtype of β-adrenergic receptor underlying the response to isoproterenol in the both age groups were examined. Endothelial removal, pre-contraction with KCl (40 mM), pre-treatment with tetraethylammonium or with Nω-Nitro-L-arginine methyl ester inhibited the vasodilator response to isoproterenol only in aortic rings from older rats. The inhibition was total when TEA and L-NAME were administered together. In both age groups the response to isoproterenol was unaffected by the β 1-adrenergic antagonist CGP20712A, but was significantly inhibited by ICI 118551 (a β 2- adrenergic-antagonist) and to a greater extent by SR 59230A (a non-selective β 3-adrenergic antagonist), the inhibition being more evident in the older rats. Unlike younger rats, in older animals the response to isoproterenol was partially dependent on endothelial nitric oxide and on K + channels. In both age groups, β 2- and β 3-, but not β 1- adrenergic receptors were involved. The degree of relative participation of β 2 and β 3 adrenergic receptors may change with age and explain the differences in response to isoproterenol.
AB - Mechanisms underlying age-dependent changes in vasodilator responses to β-adrenergic drugs are poorly understood. The aim of the current study was to compare responses to isoproterenol (a non-selective β-adrenergic receptor agonist) in phenylephrine or KCl precontracted aortic rings from 3 week and 3 month old male Wistar rats. Both the mechanism and the subtype of β-adrenergic receptor underlying the response to isoproterenol in the both age groups were examined. Endothelial removal, pre-contraction with KCl (40 mM), pre-treatment with tetraethylammonium or with Nω-Nitro-L-arginine methyl ester inhibited the vasodilator response to isoproterenol only in aortic rings from older rats. The inhibition was total when TEA and L-NAME were administered together. In both age groups the response to isoproterenol was unaffected by the β 1-adrenergic antagonist CGP20712A, but was significantly inhibited by ICI 118551 (a β 2- adrenergic-antagonist) and to a greater extent by SR 59230A (a non-selective β 3-adrenergic antagonist), the inhibition being more evident in the older rats. Unlike younger rats, in older animals the response to isoproterenol was partially dependent on endothelial nitric oxide and on K + channels. In both age groups, β 2- and β 3-, but not β 1- adrenergic receptors were involved. The degree of relative participation of β 2 and β 3 adrenergic receptors may change with age and explain the differences in response to isoproterenol.
UR - http://www.scopus.com/inward/record.url?scp=84555218613&partnerID=8YFLogxK
M3 - Artículo
SN - 0083-8969
VL - 53
SP - 29
EP - 32
JO - Proceedings of the Western Pharmacology Society
JF - Proceedings of the Western Pharmacology Society
ER -