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Biomedical subjects

J Flórez

Publications and source records attributed to J Flórez.

At least 73 records · Page 4Linked to original sources

Inhibition of the activity of the respiratory and vasomotor centers by centrally administered 5-hydroxytryptamine in cats.

The influence of 5-hydroxytryptamine (5-HT) on the activity of the respiratory and vasomotor centers was studied by injecting 5-HT into the lateral and fourth ventricles of lightly anaesthetized cats. 50 and 500 mu g of 5-HT injected into the lateral ventricle induced a shortlasting increase in frequency and/or tidal volume followed by a prolonged and dose-dependent reduction of frequency, tidal volume and minute volume, concurrent with an increase in end expiratory CO2. The CO2 responsiveness of the respiratory center was depressed and the blood pressure levels were also lowered. All these effects were markedly enhanced by monoamine oxidase inhibition with i.v. tranylcypromine injected 75 min prior to 5-HT. 50 mu g of 5-HT injected into the fourth ventricle induced a depression of respiration similar to that observed in the lateral ventricle studies, with the exception that the early stimulation was abolished.

Anesthesia↗

Respiratory responses to opiates applied to the medullary ventral surface.

The participation of the medullary structures in the total respiratory effect of opiates was studied by restricting the access of the delta-agonist D-ala2-D-leu5-enkephalin and the mu-agonist D-ala2-Me-Phe4-Met (O) ol5-enkephalin, to the ventral medullary surface, and by comparing their responses with those induced after i.c.v. administration. The medullary structures were more resistant to the overall depressant action. The opioids in the medulla depressed preferentially the tidal volume and the CO2-responsivity whereas the i.c.v. injections affected severely the frequency. No qualitative differences were found between the effects of the delta- and mu-agonist. It is concluded that both, medullary and supramedullary structures are involved in the respiratory response to opiates, but they participate with unique functions in the overall respiratory effect.

Animals↗