RESUMO
In diabetic patients, impairment of wound healing is a serious problem which represents a significant health burden. The effect of a highly selective beta-3 adrenoceptor agonist, SR58611A, on wound healing was assessed in animal models of type II diabetes. In db/db diabetic mice, a daily oral treatment with SR58611A (1, 3 and 10 mg/kg/day for two weeks) significantly reduced hyperglycaemia from 3 mg/kg/day onwards. The compound also normalized wound healing, starting from the lowest dose tested (1 mg/kg/day). SR58611A did not affect wound healing of control (lean) mice. An oral anti-diabetic agent, devoid of affinity for beta-3 adrenoceptors, troglitazone (130 mg/kg/day p.o.), normalized glycaemia but did not improve wound healing in db/db mice. Local application of SR58611A (200 microg/day in db/db mice) did not affect wound healing. SR58611A also normalized glucose levels in ob/ob mice, but only slightly improved wound healing in this strain. Moreover, in 17-week old db/db mice (i.e. severely insulin resistant) and in streptozotocin-induced diabetic mice, SR58611A slightly decreased hyperglycaemia and did not affect wound healing. In conclusion, SR58611A improves wound healing in animal models of non-insulin-dependent diabetes. This effect is not related to its effect on glucose levels, but probably implicates systemic effects of the compound.
Assuntos
Agonistas de Receptores Adrenérgicos beta 3 , Agonistas Adrenérgicos beta/uso terapêutico , Diabetes Mellitus Experimental/fisiopatologia , Obesidade/fisiopatologia , Tetra-Hidronaftalenos/uso terapêutico , Cicatrização/efeitos dos fármacos , Administração Oral , Agonistas Adrenérgicos beta/administração & dosagem , Agonistas Adrenérgicos beta/farmacologia , Animais , Glicemia/análise , Diabetes Mellitus Experimental/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Pele/efeitos dos fármacos , Pele/lesões , Pele/patologia , Tetra-Hidronaftalenos/administração & dosagem , Tetra-Hidronaftalenos/farmacologia , Fatores de TempoRESUMO
We studied the delay in gastric emptying and gastrointestinal transit induced by the cannabinoid receptor agonists (+)-WIN 55,212-2 (R(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone mesylate) and CP 55,940 ((-)-cis-3[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol), as prevented by the selective cannabinoid CB(1)-receptor antagonist SR141716 ((N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide)) in rats after systemic or central drug administration. Oral SR141716 showed comparable potency (ID(50) range 1.0-3.9 mg/kg) in antagonizing gastric emptying and gastrointestinal transit delay by (+)-WIN 55,212-2 or CP 55,940. Gastric emptying and gastrointestinal transit delay after intracerebroventricular (i.c.v.) (+)-WIN 55,212-2 was prevented by oral or i.c.v. SR141716, but i.c.v. SR141716 did not significantly reduce the effect of i.p. (+)-WIN 55,212-2. Pertussis toxin prevented the delaying action of i.c.v. (+)-WIN 55,212-2 on both gastric emptying and gastrointestinal transit, but had no effect on (+)-WIN 55,212-2 i.p. These findings are consistent with a primary role of peripheral cannabinoid CB(1) receptor mechanisms in gastrointestinal transit delay by specific agonists.