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Cardiovascular responses to verapamil and nifedipine in hypoventilated and hyperventilated rats
Author(s) -
Achike Francis I.,
Dai Soter
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb12059.x
Subject(s) - verapamil , hyperventilation , nifedipine , anesthesia , blood pressure , heart rate , medicine , hypoventilation , calcium , respiratory system
1 The influence of hypoventilation or hyperventilation on blood pressure and pulse rate responses to verapamil and nifedipine was studied in chloralose‐anaesthetized rats. 2 Artificial ventilation with room air at a fixed volume of 10 ml kg −1 successfully induced combinations of hypoxaemia, hypercarbia and acidosis at a ventilator rate of 37 strokes min −1 and of hyperoxaemia, hypocarbia and alkalosis at 160 strokes min −1 . 3 Hypoventilation caused significant decreases in both the blood pressure and pulse rate, whereas hyperventilation produced significant increases in these parameters. 4 In the controls, intravenous injections of graded doses of either verapamil or nifedipine caused dose‐dependent decreases in mean blood pressure. The effects on pulse rate were not marked. 5 The hypotensive effects of verapamil were significantly more intense in hyperventilated rats, whereas those of nifedipine were significantly less pronounced in hypoventilated animals. The hypoventilated rats exhibited a significant dose‐dependent decrease in pulse rate in response to verapamil administration. 6 It is concluded that cardiovascular responses to verapamil, nifedipine and probably other calcium antagonists are altered in the presence of blood gas abnormalities.