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M Nassif

Publications and source records attributed to M Nassif.

9 recordsLinked to original sources

Lethal effect of the serotonin-xylocaineR association in ganglion-blocked rats.

In rats anestetized with urethane and under ganglionic blockade by hexamethonium (20 mg/kg, i.v.), the i.v. injection of serotonin (60 mug/kg) determined apnea, ECG alterations and a brief hypotensive response which is similar to that as elicited when 5-HT is given to intact rats. During the hypertension which follows that initial response, apnea is still present along with more severe ECG changes. After that, blood pressure falls into a prolonged hypotension, which is invariably accompanied by death. Neither norepinephrine, nor respiratory analeptics (CoramineR, RemeflinF) were able to prevent the fatal outcome. Only artificial respiration was found to be useful in some instances. It was concluded that the association serotonin plus lidocaine becomes lethal when given to ganglion-blocked rate, and this toxic effect can be ascribed mainly to the respiratory depressor activity of the drugs.

Animals

[Sensitization of bradycardia during final hypotension induced by serotonin in rats: effect of lidocaine].

It was studied the sensibilizing effect of lidocaine (8.5 mg/kg, i.v.) on the ECG (heart rate, P-R interval, QRS complex and Q-T interval) of both intact and bilaterally vagotomised rats, in the nadir of the final hypotension determined by serotonine (60 mug/kg, i.v.). The results showed (1) a certain degree of selectivity of the vagi, and (2) the effects of serotonine either isolated or associated to lidocaine on P-R interval and heart rate were reinforced when intact animals were used. Although no significant alterations of Q-T were elicited by the drugs, lidocaine surprisingly enlarged the QRS complex in a more significant fashion for the intact than for the vagotomised animals.

Animals