Exploring the Impact of Persistent Morphine Exposure on Kindling Susceptibility in Rat Models

Background: Epilepsy is a complex neurological disorder. The relationship between this condition and morphine is intricate and not yet fully understood. Objectives: This study aims to explore the complex relationship between epilepsy and morphine to shed light on their interactions. The main goal is to better understand how morphine can affect seizure thresholds and how a history of epilepsy may alter a patient’s response to morphine. Methods: Forty male Wistar rats were divided into four groups: Control (normal saline [1 mL/kg, intraperitoneally]+pentylenetetrazol [PTZ] [35 mg/kg, intraperitoneally]), morphine 2 (morphine [2 mg/kg, intraperitoneally]+PTZ [35 mg/kg, intraperitoneally]) and morphine 10 (morphine [10 mg/kg, intraperitoneally]+PTZ [35 mg/kg, intraperitoneally]) and diazepam (diazepam [10 mg/kg, intraperitoneally]+PTZ [35 mg/kg, intraperitoneally]). PTZ (35 mg/kg, intraperitoneally, 10 weeks) was administered to induce kindling, and local field potentials were recorded for 10 minutes. Diazepam was administered to terminate the PTZ-induced epileptiform activity. Results: Seizures commenced within less than 100 s and morphine administration did not affect the onset time. The groups that received doses of 2 and 10 mg/kg morphine experienced a significant increase in mean spike counts (P>0.05); in contrast, the mean amplitude remained unaffected compared to the control group. Conclusion: The study found that while morphine may increase the frequency of epileptiform activity induced by the chemical agent PTZ, it does not alter the strength of the electrical activity, which can be a crucial consideration when evaluating the potential use of morphine in the management of seizures.