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Methadone's effects on pentylenetetrazole‐induced seizure threshold in mice: NMDA/opioid receptors and nitric oxide signaling
Author(s) -
Kazemi Roodsari Soheil,
Bahramnejad Erfan,
Rahimi Nastaran,
Aghaei Iraj,
Dehpour Ahmad Reza
Publication year - 2019
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/nyas.14043
Subject(s) - naltrexone , methadone , nmda receptor , pharmacology , seizure threshold , opioid , nitric oxide , chemistry , nitric oxide synthase , glutamate receptor , opioid receptor , anesthesia , epilepsy , receptor , medicine , anticonvulsant , biochemistry , organic chemistry , psychiatry
Methadone is a synthetic opioid used to treat opiate withdrawal and addiction. Studies have demonstrated the impact of methadone on seizure susceptibility. This study investigated the modulatory impacts of acute and subchronic (three times daily for 5 days) intraperitoneal methadone treatment on pentylenetetrazole‐induced clonic seizure threshold (CST) in mice, as well as the involvement of the nitric oxide, N ‐methyl‐ d ‐aspartate (NMDA), and µ‐opioid pathways. Acute administration of different doses of methadone (0.1, 0.3, 1, and 3 mg/kg) 45 min before CST significantly decreased the seizure threshold. Additionally, pretreatment with noneffective doses of an opioid receptor antagonist (naltrexone) and NMDA receptor antagonists (ketamine and MK‐801) inhibited methadone's proconvulsive activity in the acute phase, while l ‐NAME (a nonspecific nitric oxide synthase (NOS) inhibitor) did not affect that activity. In the subchronic phase, methadone (3 mg/kg) demonstrated an anticonvulsive effect. Although subchronic pretreatment with noneffective doses of l ‐NAME and 7‐nitroindazole (a specific neuronal NOS inhibitor) reversed methadone's anticonvulsive activity, aminoguanidine (a specific inducible NOS inhibitor), naltrexone, MK‐801, and ketamine did not change methadone's anticonvulsive characteristic. Our results suggest that NMDA and µ‐opioid receptors may be involved in methadone's proconvulsive activity in the acute phase, while methadone's anticonvulsive activity may be modulated by neuronal NOS in the subchronic phase.