RESUMO
Experiments on rats showed that injection of propranolol into the medulla oblongata increased the contents of epinephrine, norepinephrine, dopamine, and L-DOPA by 3.76, 1.4, 2.0, and 1.7 times, respectively. These propranolol-induced changes in the levels and ratio of neurotransmitters were not accompanied by variations in serotonin content. Propranolol had no significant effects on the content of excitatory amino acids, except marked increase in aspartate content. The level of inhibitory amino acids increased mainly due to an increase in GABA content. The balance between excitatory and inhibitory amino acids was shifted towards inhibitory compounds.
Assuntos
Glândulas Suprarrenais/efeitos dos fármacos , Antagonistas Adrenérgicos beta/farmacologia , Catecolaminas/metabolismo , Bulbo/fisiologia , Propranolol/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Glândulas Suprarrenais/metabolismo , Aminoácidos/metabolismo , Animais , Masculino , Bulbo/efeitos dos fármacos , Distribuição Aleatória , Ratos , Serotonina/metabolismo , Sistema Nervoso Simpático/fisiologia , Ácido gama-Aminobutírico/metabolismoRESUMO
Local injection of verapamil into ventrolateral region of the medulla oblongata triggered the release of epinephrine. Verapamil increased the total content of norepinephrine and epinephrine by 560% and decreased the content of serotonin by 46%. Verapamil had no effect on norepinephrine/epinephrine and norepinephrine/(norepinephrine+epinephrine) ratios in normal rats. Blockade of K+-channels in the medulla oblongata by local injection of 0.001 mg amiodarone did not change the levels of epinephrine and norepinephrine and norepinephrine/epinephrine and norepinephrine/(norepinephrine+epinephrine) ratios. In the medulla oblongata, verapamil proportionally increased the levels of norepinephrine, dopamine, and L-DOPA. Similarly, amiodarone increased the levels of L-DOPA and dopamine by 2.6 and 3.2 times, respectively. Amiodarone shifted the ratio of neuroactive amino acids towards inhibitory transmitters.