title: Role of γ-aminobutyric acid signalling in the attenuation of counter-regulatory hormonal responses after antecedent hypoglycaemia in healthy men.
abstract: The attenuated counter-regulatory response to hypoglycaemia after antecedent hypoglycaemic episodes has been observed in animals to be associated with an increase in γ-aminobutyric acid (GABA) signalling. We therefore tested the hypothesis that the pharmacological suppression of GABAergic activity during a repeated hypoglycaemic episode enhances counter-regulatory responses. Fourteen healthy men participated in two experimental sessions each comprising three insulin-induced hypoglycaemic episodes. Before the third hypoglycaemic episode, participants received the GABA-antagonistic drug modafinil (200 mg orally) and placebo, respectively. In the placebo condition, the secretion of norepinephrine, adrenocorticotropic hormone, cortisol and growth hormone, and the perception of neuroglycopenic symptoms were attenuated during the third as compared with the first hypoglycaemic episode (each p < 0.05). Modafinil reversed this effect for the noradrenergic response (p < 0.05), while not significantly altering the attenuation of other hormonal responses and symptom perception (p > 0.3). Our findings indicate that increased GABAergic transmission could contribute to aspects of the attenuated counter-regulatory response after recurrent hypoglycaemia in humans.
authors: Department of Internal Medicine I, University of Lübeck, Lübeck, Germany.
authors: J
authors: J
authors: Klement
authors: B
authors: B
authors: Mergelkuhl
authors: J
authors: J
authors: Born
authors: H
authors: H
authors: Lehnert
authors: M
authors: M
authors: Hallschmid
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000187:drug effects; D000328:Adult; D000704:Analysis of Variance; D001559:Benzhydryl Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D065701:Cytochrome P-450 CYP3A Inducers / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D013006:Growth Hormone / Q000097:blood / Q000187:drug effects; D064368:Healthy Volunteers; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007003:Hypoglycemia / Q000139:chemically induced*; D008297:Male; D000077408:Modafinil; D009638:Norepinephrine / Q000097:blood; D015398:Signal Transduction / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001559:Benzhydryl Compounds; D001786:Blood Glucose; D065701:Cytochrome P-450 CYP3A Inducers; D005680:gamma-Aminobutyric Acid; D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D000077408:Modafinil; D006854:Hydrocortisone; D009638:Norepinephrine
keywords: diabetes complications; diabetes mellitus; glucose metabolism; neuropharmacology