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J Flórez

Publications and source records attributed to J Flórez.

76 records · Page 5Linked to original sources
PubMedDate not supplied

Comparative effects of opioid peptides on respiration and analgesia in rats.

Receptor mechanisms for opiate induced respiratory depression and analgesia (tail-flick) were studied by the ED50 ratios and the apparent pA2 values of the interactions of naloxone with the mu-agonists morphine and D-ala2-me-phe4-met (O)ol5-enkephalin (FK-33824), and the delta-agonists D-ala2-D-leu5-enkephalin (DADL) and tyr-D-ser-gly-phe-leu-thr. The apparent pA2 values of morphine, FK-33824 and DADL for analgesia were similar, whereas the apparent pA2 values of the mu-agonists for respiratory depression were significantly lower than those of the delta-agonists. The ratio between the ED50 of FK-33824 in analgesia and respiratory depression was much lower than that of DADL. It is concluded that different receptors mediate the opiate-induced respiratory depression. One difficulty with the delta-receptors being maximally involved in this action is the high degree of antagonism shown by naloxone on the respiratory effects of the delta-agonists.

Analgesia↗
PubMedDate not supplied

Respiratory actions induced by cholecystokinin at the brainstem level.

A functional differentiation of the action of cholecystokinin octapeptide (CCK-8) on the respiratory centers was accomplished by the topical application to the ventral surface of the medulla and to the dorso-rostral pontine surface in cats. In the medulla, CCK-8S at doses ranging from 0.09 nmol to 0.88 nmol, stimulated tidal volume in a dose-dependent fashion, with minimal or no changes in frequency. The antagonist proglumide (30 nmol) inhibited specifically the action on the respiratory amplitude. In the pons, CCK-8S did not modify the respiratory activity even at the dose of 8.8 nmol. The results suggest a specific involvement of CCK-8S in the mechanisms controlling respiratory amplitude, which appear mostly restricted to the medullary level. The lack of effect of the peptide in the pons is in agreement with the absence of CCK receptors in the respiration related nuclei located at that level, as evidenced by autoradiographic studies.

Animals↗