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Biomedical subjects

E Rubio

Publications and source records attributed to E Rubio.

131 records · Page 8Linked to original sources
PubMedDate not supplied

Interaction between histamine and clonidine in isolated guinea-pig atria.

1. This study investigates the chronotropic and inotropic effects of clonidine and its interaction with histamine in spontaneously beating and electrically driven isolated guinea-pig atria. 2. Clonidine (up to 100 microM) did not modify the force of contraction in either spontaneously beating or paced atria. 3. Clonidine increased the rate of beating, having a lower maximal effect (43 +/- 5%) and a higher EC50 (15.7 +/- 4 microM) than histamine (Emax = 100%; EC50 = 1.47 +/- 0.1 microM). 4. The positive chronotropic effect of clonidine was unchanged after clemizole, phentolamine, propranolol and atropine but was competitively antagonized by cimetidine (pA2 = 6.87 +/- 0.18). 5. Concentration-response curves for clonidine in the presence of several concentrations of histamine, and for histamine in the presence of several concentrations of clonidine, were constructed and the displacements observed with respect to the control curves in each case fit the competitive dualism model. 6. These results demonstrate that clonidine behaves as a partial agonist of the histamine H2-receptor in isolated guinea-pig atria.

Animals↗
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Exercise-induced asthma prophylaxis in athletes using inhaled nedocromil sodium.

This open labelled, group comparative, cross over study, was carried out to analyze the efficacy of two dosages of Nedocromil sodium (NS) in the prophylaxis of Exercise Induced Asthma (EIA). 13 athletes (6 males, 7 females), aged: 12-38 years, were studied measuring their EIA by forced spirometries prior and at 1, 3, 5, 10, 15 and 30 minutes post treadmill test. Four mg of NS were administered via inhalation chamber 30 minutes prior to the second test; prior to the third one;: NS at a dose of 4 mg every 8 hours during four weeks plus 4 mg of NS 30 minutes before it. In the baseline exercise test, a 33.6 +/- 10.5 percent decrease of FEV1 was observed; 12.6 +/- 11.4 in the second one, and 9.7 +/- 9.76 in the third test. A protection index higher than 30% was obtained in 9 cases of the second test (81.5 +/- 16.2%), and in 10 of the third one (77.2 +/- 15.3%). Nedocromil sodium (4 mg prior to exercise) is effective for EIA prophylaxis. Although no significant differences exist between both dosages, a greater protection index is reached after NS sustained administration.

Adolescent↗