title: The possible role of medial prefrontal cortex beta-1-adrenoceptors in morphine-induced amnesia.
abstract: The prelimbic region of the medial prefrontal cortex (mPFC) in the brain is crucial for memory. Norepinephrine elicits an important influence on mPFC functions. The stimulation of β-adrenoceptors (β-ARs) may play a critical role in the consolidation of long-term memory. The present study examines the possible role of β₁-ARs located in the mPFC on morphine-induced amnesia in rats. The animals were bilaterally implanted with chronic cannulas in the mPFC, trained in a step-through-type passive avoidance task and tested 24 h after training to measure step-through latency. Our present results indicated that posttraining intraperitoneal administration of morphine (2.5, 5 and 7.5 mg/kg) dose-dependently reduced the step-through latency. Different doses of xamoterol (0.01, 0.1 and 1 µg/rat) have shown no significant change in the step-through latency, but posttraining intra-mPFC microinjection of atenolol (0.2 and 0.4 µg/rat) had an amnesic effect. Moreover, atenolol-caused amnesia was reversed by an ineffective dose of xamoterol (0.1 µg/rat). On the other hand, coadministration of an ineffective dose of atenolol (0.1 µg/rat) with an ineffective dose of morphine (2.5 mg/kg) induced an amnesic effect. Meanwhile, xamoterol had no effect on morphine-induced amnesia. These results suggest that β₁-ARs of the prelimbic region in the mPFC may play an important role in morphine-induced amnesia.
authors.affiliation: Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Anahita
authors.initials: A
authors.lastname: Torkaman-Boutorabi
authors.forename: Seyed-Milad
authors.initials: SM
authors.lastname: Hashemi-Hezaveh
authors.forename: Hadi
authors.initials: H
authors.lastname: Sheidadoust
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Zarrindast
mesh_terms: D058665:Adrenergic beta-1 Receptor Agonists / Q000494:pharmacology; D058671:Adrenergic beta-1 Receptor Antagonists / Q000494:pharmacology; D000647:Amnesia / Q000139:chemically induced / Q000503:physiopathology*; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001362:Avoidance Learning / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects; D009020:Morphine; D017397:Prefrontal Cortex / Q000502:physiology*; D017208:Rats, Wistar; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*; D017307:Xamoterol / Q000494:pharmacology
chemical_list: D058665:Adrenergic beta-1 Receptor Agonists; D058671:Adrenergic beta-1 Receptor Antagonists; D018342:Receptors, Adrenergic, beta-1; D001262:Atenolol; D009020:Morphine; D017307:Xamoterol