Intracoerulear microinjection of orexin-A induces morphine withdrawal-like signs in rats.

Intracoerulear microinjection of orexin-A induces morphine withdrawal-like signs in rats. Brain Res Bull. 2017 Jan 13;: Authors: Ghaemi-Jandabi M, Azizi H, Ahmadi-Soleimani SM, Semnanian S Abstract Orexin (hypocretin) neuropeptides play a pivotal role in expression of opioid withdrawal signs. Hypothalamic orexinergic neurons provide dense afferents for the nucleus locus coeruleus (LC). Somatic signs of opioid withdrawal are associated with the enhanced activity of LC neurons. In addition, intra-LC administration of orexin-A leads to the hyperactivity of LC neurons. The present study was an attempt to investigate whether intra-LC microinjection of orexin-A induces morphine withdrawal-like signs in both morphine dependent and control rats. To end this, adult male Wistar rats weighing 250-300g were used. For induction of morphine dependence, animals received morphine sulfate subcutaneously (10mg/kg,s.c.) at an interval of 12h for 9 days. On day 10, intra-LC orexin injection (100μM, 200 nl) was carried out two hours after last morphine administration. Morphine withdrawal-like signs were assessed in a transparent Plexiglas test chamber (30cm diameter, 50cm height) for 25minutes. Orexin-A microinjection induced some morphine withdrawal-like signs in both morphine dependent (chewing, scratching, rearing, teeth chattering, wet-dog shake and paw tremor) and control (chewing, scratching, rearing, sniffing, wet-dog shake and head tremor) rats....
Source: Brain Research Bulletin - Category: Neurology Authors: Tags: Brain Res Bull Source Type: research