Does Experimental Morphine Addiction in Rats Change Physiological and Histological Characteristics of the Heart?

Aim: Morphine is one of the most preferred opioids in treatment of chronic pain. Recurrent use can
cause addiction. There is no consensus on cardiovascular system treatment/side effects of opioids. In
order to investigate effects of opioid addiction on heart, myocardial contractility/histological changes were
investigated in rats via experimental morphine addiction/withdr awal.
Materials and Methods: 32 adult male Wistar albino rats used for study, which was officially completed
on 28-05-2021, were divided into Control(C), Morphine(M), Morphine+Naloxone(MN) groups randomly. In
GroupC 10mg/kg 0.9% NaCl solution, in GroupM-MN 10mg/kg morphine were administered subcutaneously
for 7 days. After the last administration of morphine, 3mg/kg NaCl was given to GroupC-M, 3mg/kg naloxone
was given to GroupMN intraperitoneally. Signs of morphine withdrawal were observed for 30 minutes
and scored. 3-4mm strips of atria were hung in isolated organ bath chambers. Tension was adjusted to
2g. Adrenaline-induced contractions (0.001M) were observed. Changes in tension were recorded. SAS
University Edition 9.4 program was used for statistical analysi s.
Results: Morphine withdrawal behaviours were observed in GroupMN. There was no statistically
significant difference between atrial contractility tension values of GroupC-M-MN(p>0.05). Pre-adrenaline
tension values were higher in GroupM-MN than in GroupC. But the greatest contraction increase between
15minutes before/after adrenaline-induced data was in GroupC.
Conclusion: Morphine addiction/withdrawal didn’t cause inotropic/chronotropic changes. No histological
differences were observed in mast cells. These results may constitute a positive resource for the heart for
systems analysis in morphine addicts.