RESUMO
We studied the mechanisms of combined action of clonidine and local anesthetics amethocaine and imidazo-benzimidazole derivative RU-1117. In contrast to amethocaine, RU-1117 in therapeutic concentrations binds to imidazoline receptors and, to a lesser extent, to alpha(2A)-adrenoceptors on human platelets. Clonidine and RU-1117 produce opposite effects on platelet aggregation induced by ADP in low concentrations. Our results suggest that the pharmacodynamic interaction of clonidine and RU-1117 is associated with their ability to activate the imidazolinergic system.
Assuntos
Anestésicos Locais/farmacologia , Benzimidazóis/farmacologia , Clonidina/farmacologia , Difosfato de Adenosina/metabolismo , Agonistas alfa-Adrenérgicos/farmacologia , Benzimidazóis/química , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Humanos , Receptores de Imidazolinas , Concentração Inibidora 50 , Agregação Plaquetária/efeitos dos fármacos , Ligação Proteica , Receptores Adrenérgicos alfa 2/metabolismo , Receptores de Droga/química , Tetracaína/farmacologia , Fatores de TempoRESUMO
In isometric efforts small energy expenditure was found to involve an inadequate increase of the heart rate and blood pressure. In dynamic cyclic loads, the heart rate and blood pressure increase occurs linearly, corresponding to the increase of O2 consumption and systolic index. Voluntary relaxation of muscles in the course of cyclic load involves small values of the O2 consumption and systolic index, as well as low heart rate and blood pressure. In natural cyclic and noncyclic motor activity, the character of integration of the motor and vegetative functions depends on the relative weight of each of the biomechanical modes.
Assuntos
Sistema Nervoso Autônomo/fisiologia , Atividade Motora/fisiologia , Músculos/fisiologia , Esforço Físico , Adolescente , Adulto , Frequência Cardíaca , Hemodinâmica , Humanos , Contração Isométrica , Masculino , Consumo de Oxigênio , RespiraçãoAssuntos
Hemodinâmica , Respiração , Fenômenos Biomecânicos , Volume Sanguíneo , Humanos , Movimento , Contração Muscular , Relaxamento Muscular , Esforço FísicoRESUMO
In conditions of enhanced motivation trained subjects performed a greater work and untrained ones--a lesser work than under ordinary motivation. The most stable parameters in regard to working to capacity were as follows: heart rate, minute respiratory volume, amount of oxygen consumption, amount of exhaled CO2, energy expenditure, and oxygen pulse. The data obtained show that untrained subjects under ordinary and, particularly, enhanced motivation for working to capacity are able to mobilize a lesser amount of the organism's physiological reserves than trained people.
