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Titolo:
The potential antidiabetic activity of some alpha-2 adrenoceptor antagonists
Autore:
Abdel-Zaher, AO; Ahmed, IT; El-Koussi, AEA;
Indirizzi:
Univ Assiut, Fac Med, Dept Pharmacol, Assiut, Egypt Univ Assiut Assiut Egypt Assiut, Fac Med, Dept Pharmacol, Assiut, Egypt
Titolo Testata:
PHARMACOLOGICAL RESEARCH
fascicolo: 5, volume: 44, anno: 2001,
pagine: 397 - 409
SICI:
1043-6618(200111)44:5<397:TPAAOS>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
SENSITIVE K+ CHANNELS; PANCREATIC BETA-CELLS; INSULIN-SECRETION; POTASSIUM CHANNELS; ALPHA(2)-ADRENERGIC RECEPTOR; ADRENERGIC-RECEPTORS; GLUCOSE-TRANSPORTER; DIABETIC RATS; SMOOTH-MUSCLE; EFAROXAN;
Keywords:
yohimbine; efaroxan; type-1 diabetic rats; type-H diabetic rats; glibenclamide;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Abdel-Zaher, AO Univ Assiut, Fac Med, Dept Pharmacol, Assiut, Egypt Univ Assiut Assiut Egypt Dept Pharmacol, Assiut, Egypt
Citazione:
A.O. Abdel-Zaher et al., "The potential antidiabetic activity of some alpha-2 adrenoceptor antagonists", PHARMAC RES, 44(5), 2001, pp. 397-409

Abstract

The effect of alpha-2 adrenoceptor antagonists, yohimbine and efaroxan, onthe plasma glucose and insulin levels was studied in non-diabetic control,type-I (insulin-dependent) and type-II (non-insulin-dependent) diabetic rats. Pretreatment with either yohimbine or efaroxan potentiated glucose-induced insulin release in non-diabetic control rats and produced an improvement of the oral glucose tolerance and potentiated glucose-induced insulin release in type-II but not in type-I diabetic rats. Treatment with either yohimbine or efaroxan reduced the plasma glucose level and increased the plasmainsulin level of non-diabetic control and type-Il diabetic rats but not oftype-I diabetic rats. Effects of efaroxan were more marked. Pretreatment of non-diabetic control and typeII diabetic rats with either yohimbine or efaroxan inhibited clonidine-induced hyperglycaemia and suppressed or reversed clonidine-induced hypoinsulinaemia. Also, pretreatment of these animals with either yohimbine or efaroxan enhanced the hypoglycaemic and insulinotropic effects of glibenclamide. The combination of glibenclamide and efaroxanled to a synergistic increase in insulin secretion, while that of glibenclamide and yohimbine led to an additive increase. The hyperglycaemic effect of diazoxide in non-diabetic control and type-II diabetic rats was inhibited by pretreatment with either yohimbine or efaroxan. The hypoinsulinaemic effect of diazoxide in these animals was antagonized and reversed by pretreatment with yohimbine and efaroxan, respectively. In type-I diabetic rats, there was no change in the plasma glucose and insulin levels induced by the treatment of animals with each of clonidine or diazoxide alone or in combination with either yohimbine or efaroxan. Glibenclamide produced a slight decrease in the plasma glucose level of type-I diabetic rats, at the end of the 120 min period of investigation but there was no change in the plasma insulin level. Pretreatment of these animals with either yohimbine or efaroxan produced no change in glibenclamide effects. Additionally, bath application of efaroxan or glibenclamide inhibited the relaxant effects of differentconcentrations of diazoxide on the isolated norepinephrine-contracted aortic strips, while the application of yohimbine produced insignificant changes. The combination of glibenclamide and efaroxan led to complete inhibitionof the relaxant effects of different concentrations of diazoxide, while that of glibenclamide and yohimbine did not produce such an effect. It is concluded that yohimbine, via blockade of postsynaptic alpha-2 adrenoceptors, and efaroxan, via blockade of postsynaptic alpha-2 adrenoceptors and adenosine triphosphate-sensitive potassium channels in the pancreatic beta-cell membrane, produce insulinotropic and subsequent hypoglycaemic effects. (C) 2001 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/01/20 alle ore 13:10:02