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Öğe Compound 48/80, a histamine-depleting agent, blocks the protective effect of morphine against electroconvulsive shock in mice(Assoc Bras Divulg Cientifica, 2000) Karadag, CH; Dokmeci, D; Dost, T; Ulugol, A; Dokmeci, IWe have shown that morphine has an anticonvulsive effect against maximal electroconvulsive shock (MES) in mice, and this effect is antagonized by histamine Hi-receptor antagonists. Brain histamine is localized both in neurons and in mast cells, and morphine is known to enhance the turnover of neuronal histamine and to release histamine from mast cells. In the present experiments, compound 48/80 was injected chronically (0.5 mg/kg on day 1, 1 mg/kg on day 2, 2 mg/kg on day 3, 3 mg/kg on day 4, and 4 mg/kg on day 5, twice daily, ip) to deplete mast cell contents. Morphine (0.001-10 mg/kg, ip; N = 20) produced a dose-dependent anticonvulsive effect against MES seizure in mice with non-depleted mast cells, whereas it did not exert any anticonvulsive effect in mice with depleted mast cells. These results indicate that morphine produces its anticonvulsive effect against maximal electroconvulsive shock in mice by liberating histamine from mast cells.Öğe Involvement of NMDA receptors and nitric oxide in the thermoregulatory effect of morphine in mice(Springer-Verlag Wien, 2000) Ulugol, A; Dost, T; Dokmeci, D; Akpolat, M; Karadag, CH; Dokmeci, IMorphine has long been known to have potent effects on body temperature. It has been suggested that both N-methl-D-aspartate (NMDA) receptors and nitric oxide (NO) pathway are involved in thermoregulation and also known to play important roles in some of morphine effects. The aim of this study was therefore to investigate the contribution of NMDA receptors and NO to the thermoregulatory effect of morphine. Morphine produced a hypothermic effect, especially at the dose of 10 mg/kg. Ketamine (5-40 mg/kg, i.p.) and N-G-nitro-L-arginine-methyl ester (L-Name, 1-100 mg/kg i.p.) also produced hypothermic effects with their higher doses. At doses which themselves produced no effect on colonic temperature in mice, both ketamine (10 mg/kg, i.p.) and L-NAME (10 mg/kg, i.p.) enhanced the hypothermic effect of morphine (10 mg/kg i.p.). These results further support the relationship between NO and NMDA receptors and suggest a possible role of NMDA-NO pathway in the thermoregulatory effect of morphine.Öğe The role of nitric oxide in the protective effect of insulin against pentylenetetrazole-induced seizures in mice(John Wiley & Sons Ltd, 2000) Ulugol, A; Arikan, E; Dost, T; Dokmeci, D; Karadag, HC; Dokmeci, IBoth insulin, depending on the glycemic state, and nitric oxide (NO), depending on the experimental conditions, have been suggested to have either proconvulsant or anticonvulsant effects. It is also known that NO plays an important role in some of the peripheral effects of insulin. The aim of the present study was to investigate the effects of NO and insulin against convulsions produced by pentylenetetrazole (PTZ, 60 mg/kg, i.p.) in mice and whether NO plays a role in the effect of insulin. Nitric oxide synthase (NOS) inhibitor, N-G-nitro-L-arginine-methyl ester (L-NAME, 1-100 mg/kg, i.p.) shortened the onset of PTZ-induced convulsions and increased the incidence and mortality rate, at the higher doses. Insulin (1 U/kg, i.p.), when given with dextrose (3 g/kg, i.p.) to counteract the hypoglycemic effect of the hormone, prolonged the onset of convulsions and decreased the incidence and mortality rate. L-NAME pretreatment (3 mg/kg, i.p.), at the dose which it produced no effect on PTZ-induced convulsions, attenuated the protective effect of 1 U/kg insulin + 3 g/kg dextrose combination significantly. Concomitant administration of the NO synthesis precursor, L-arginine (500 mg/kg), completely reversed this facilitatory effect of L-NAME. Our results indicate that NO has a protective effect against PTZ-induced convulsions in mice; insulin has a similar effect when given with dextrose; and, NO production may play an important role in the anticonvulsant effect of insulin.Öğe The role of nitric oxide in the protective effect of insulin against pentylenetetrazole-induced seizures in mice [Meeting Abstract](Springer-Verlag, 2000) Ulugol, A; Arikan, E; Dost, T; Dokmeci, D; Karadag, H; Dokmeci, I[Abstract Not Available]
