Cardiovascular effect of nifedipine in morphine dependent rats: hemodynamic, histopathological, and biochemical evidence.
OBJECTIVE
To investigate whether administration of nifedipine has considerable therapeutic effect in morphine-dependent rats.


METHODS
Sixty animals were randomized into control, morphine, morphine plus nifedipine, and morphine plus dimethyl sulfoxide (DMSO, as nifedipine soluble) groups. Each group consisted of two subgroups, with and without heart injury. The groups were treated with incremental doses of morphine or morphine plus nifedipine daily for 7 days. Myocardial injury was induced by isoproterenol (50 mg/kg i.p.) on the day 7. On the day 8, the heart rate (HR), blood pressure (BP), rate-pressure product (RPP), and the plasma level of cardiac troponin I were measured and the hearts were histopathologically examined.


RESULTS
In morphine-dependent rats, nifedipine administration was associated with a significantly higher decrease in the plasma level of cardiac troponin I than the administration of morphine alone. This finding was also significant in dependent animals that received only DMSO. HR, BP, RPP, and histopathological indices did not show significant changes in the presence of nifedipine.


CONCLUSIONS
Administration of nifedipine failed to show a significant therapeutic effect in morphine-dependent rats, especially in the group with myocardial injury.
Neuroscience Research Center, Physiology Research Center and Department of Physiology and Pharmacology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran. sjokar@gmail.com
Siyavash
S
Joukar
Mohammad
M
Sheibani
Farzin
F
Joukar
D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006335:Heart Injuries / Q000139:chemically induced / Q000150:complications* / Q000473:pathology; D006339:Heart Rate / Q000187:drug effects; D007545:Isoproterenol; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009021:Morphine Dependence / Q000150:complications*; D009543:Nifedipine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019210:Troponin I / Q000097:blood / Q000187:drug effects
D000701:Analgesics, Opioid; D002121:Calcium Channel Blockers; D019210:Troponin I; D009020:Morphine; D009543:Nifedipine; D007545:Isoproterenol; D004121:Dimethyl Sulfoxide