The mechanism of chronotropic activity of caffeine and theophylline in guinea pigs

Ispitivano je djelovanje kofeina i teofilina na frekvenciju rada izoliranog desnog atrija zamorčadi. Nađeno je da kofein a mnogostruko jače teofiilin uzrokuju pozitivno kronotropno djelovanje. Reserpin i alfa-metil DOPA smanjuju pozitivno kronotropnu aktivnost ispitivanih metilksantina. Propranolol uzrokuje bradikardiju, koju naknadno dani metilksantini još više pojačavaju.The chronotropic activity of caffeine and theophylline on the isolated right atrium of the guinea pig was examinated. Theophylline caused a significant and caffeine only a slight increase in the atrial rate. Reserpine and alpha methyl DOPA diminished the chronotropic activity of the Investigated methyl xanthines. Propranolol caused a decrease in the atrial rate. Caffeine and theophylline potentiated the negative chronotropic activity of propranolol

The mechanism of chronotropic activity of caffeine and theophylline in guinea pigs

Ispitivano je djelovanje kofeina i teofilina na frekvenciju rada izoliranog desnog atrija zamorčadi. Nađeno je da kofein a mnogostruko jače teofiilin uzrokuju pozitivno kronotropno djelovanje. Reserpin i alfa-metil DOPA smanjuju pozitivno kronotropnu aktivnost ispitivanih metilksantina. Propranolol uzrokuje bradikardiju, koju naknadno dani metilksantini još više pojačavaju.The chronotropic activity of caffeine and theophylline on the isolated right atrium of the guinea pig was examinated. Theophylline caused a significant and caffeine only a slight increase in the atrial rate. Reserpine and alpha methyl DOPA diminished the chronotropic activity of the Investigated methyl xanthines. Propranolol caused a decrease in the atrial rate. Caffeine and theophylline potentiated the negative chronotropic activity of propranolol

Humoral and cell-mediated immune responses following lesions of the nucleus basalis magnocellularis in the rat

The present study was undertaken to elucidate whether electrolytic lesions of nucleus basalis magnocellularis-NBM (an animal model of Alzheimer's disease-AD) may influence humoral and cellular immune responses in adult male Wistar rats. For this purpose intact control (IC), sham-operated (SO) and NBM-lesioned rats were divided into two main groups: (1) rats immunized with sheep red blood cells (SRBC) for plaque-forming cell (PFC) response and anti-SRBC agglutinins, and (2) rats immunized with bovine serum albumin in complete Freund's adjuvant (BSA-CFA) for anti-BSA antibody production, Arthus and delayed hypersensitivity skin reaction to BSA. PFC responses and anti-SRBC agglutinins as well as diameter and expression of edema/induration of Arthus/delayed skin reaction and titer of anti-BSA antibody were significantly lower in NBM lesioned rats (compared to IC and SO). The results showed that in NBM-lesioned rats both the humoral and cellular immune responses were suppressed

Behavioral and adaptive status in an experimental model of Alzheimer's disease in rats

Ten days after bilateral electrolytic lesions of nucleus basalis magnocellularis (NBM) we tested behavioral (spontaneous motor activity, acquisition and performance of two-way active avoidance, fear-response in open field test, foot shock induced aggression, depression-response in learned helplessness test) and adaptive status (body temperature at standard, hot and cold environment as well as cold restraint-induced gastric lesions) in adult male Wistar rats. Compared to intact control and sham-operated rats, the bilateral NBM-lesioned rats showed the significant impairment of learning behavior and reduced fear, aggression and depression as well as altered body temperature at standard and stressed conditions. Namely, it was established that body temperature in NBM-lesioned rats was significantly lower at standard laboratory conditions, but in these rats body temperature significantly was raised after exposing to cold and hot environment. On the other hand, spontaneous motor activity and number and length of cold restraint-induced gastric lesions (erosions and petechiae) in NBM-lesioned rats were similarly to those in both controls. It could be concluded that NBM plays a significant role in cognitive, emotional and adaptive processes in the rats

Effect of physostigmine and verapamil on active avoidance in an experimental model of Alzheimer's disease

The present study was performed to investigate and compare the effect of acetylcholinesterase inhibitor, physostigmine (0.045, 0.060 and 0.075 mg/kg sc, 30 min before the tests) and Ca-antagonist, verapamil (1.0, 2.5, 5.0 and 10.0 mg/kg sc, 30 min before the tests), on two-way active avoidance (AA) learning (acquisition and performance) in nucleus basalis magnocellularis (NBM)-lesioned rats. Bilateral electrolytic lesions of NBM induced significant decrease of acquisition and performance of AA responses in rats. Physostigmine (0.060 mg/kg) significantly improved only acquisition of AA, while verapamil (2.5 and 5.0 mg/kg) significantly improved both type of AA behavior in NBM-lesioned rats. These results suggest that altered calcium homeostasis might play significant role in pathogenesis of experimental induced Alzheimer's disease (AD) and that administration of calcium antagonist such as verapamil might successfully ameliorate disturbances of learning and memory appeared after lesions of NBM