TY - JOUR
T1 - Effects of adrenergic blockers on central nervous system-mediated hyperglycemia in fed rats
AU - Kunoh, Yasuo
AU - Iguchi, Akihisa
AU - Uemura, Kazumasa
AU - Miura, Hisayuki
AU - Tamagawa, Tatsuo
AU - Mano, Tadaaki
AU - Nonogaki, Katunori
AU - Gotoh, Minehiro
AU - Sakamoto, Nobuo
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1992/5
Y1 - 1992/5
N2 - We studied the effect of adrenergic blockade on hepatic venous hyperglycemia and the activation of a hepatic glycogenolytic enzyme, phosphorylase-a, in response to cerebral cholinergic activation. Neostigmine was injected into the third cerebral ventricle of bilaterally adrenodemedullectomized (ADMX) rats, while somatostatin and insulin were administered intravenously. Hepatic venous plasma glucose concentrations and hepatic phosphorylase-a activity were measured. Intracerebroventricular injection of neostigmine (5 × 10-8 mol) caused increases in hepatic venous glucose concentrations and hepatic phosphorylase-a activity. Both of these changes were prevented by intraperitoneal (IB) pretreatment with phentolamine (5 × 10-7, 1 × 10-6 mol) without the intervention of insulin secretion, but not by pretreatment with the α-antagonists antagonist phenoxybenzamine (1 × 10-6 mol), the β-adrenoreceptor antagonist propranolol (1 × 10-6 mol), the α1-antagonists prazosin or bunazosin (1 × 10-6 mol), the α2-antagonist yohimbine (1 × 10-6 mol), or prazosin (5 × 10-7 mol) plus yohimbine (5 × 10-7 mol). These results suggest that phentolamine prevented brain-mediated hepatic glycogenolysis by a mechanism that may not be classified pharmacologically as involving either α1- or α2-receptors.
AB - We studied the effect of adrenergic blockade on hepatic venous hyperglycemia and the activation of a hepatic glycogenolytic enzyme, phosphorylase-a, in response to cerebral cholinergic activation. Neostigmine was injected into the third cerebral ventricle of bilaterally adrenodemedullectomized (ADMX) rats, while somatostatin and insulin were administered intravenously. Hepatic venous plasma glucose concentrations and hepatic phosphorylase-a activity were measured. Intracerebroventricular injection of neostigmine (5 × 10-8 mol) caused increases in hepatic venous glucose concentrations and hepatic phosphorylase-a activity. Both of these changes were prevented by intraperitoneal (IB) pretreatment with phentolamine (5 × 10-7, 1 × 10-6 mol) without the intervention of insulin secretion, but not by pretreatment with the α-antagonists antagonist phenoxybenzamine (1 × 10-6 mol), the β-adrenoreceptor antagonist propranolol (1 × 10-6 mol), the α1-antagonists prazosin or bunazosin (1 × 10-6 mol), the α2-antagonist yohimbine (1 × 10-6 mol), or prazosin (5 × 10-7 mol) plus yohimbine (5 × 10-7 mol). These results suggest that phentolamine prevented brain-mediated hepatic glycogenolysis by a mechanism that may not be classified pharmacologically as involving either α1- or α2-receptors.
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U2 - 10.1016/0026-0495(92)90203-M
DO - 10.1016/0026-0495(92)90203-M
M3 - Article
C2 - 1350317
AN - SCOPUS:0026716388
VL - 41
SP - 471
EP - 475
JO - Metabolism: Clinical and Experimental
JF - Metabolism: Clinical and Experimental
SN - 0026-0495
IS - 5
ER -