Modulation of object memory consolidation by heroin and heroin-conditioned stimuli: Role of opioid and noradrenergic systems

• Published in: European neuropsychopharmacology Vol. 33; pp. 146 - 157
• Main Authors: Wolter, Michael, Huff, Andrew E., Baidoo, Nana, Jardine, Kristen H., Pulles, Zoey, Winters, Boyer D., Leri, Francesco
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2020
• Subjects: Conditioned stimulus; Heroin; Memory consolidation; Naltrexone; Object recognition; Propranolol; Memory consolidation; Conditioned stimulus; Object recognition; Naltrexone; Propranolol; Heroin
• ISSN: 0924-977X; 1873-7862
• DOI: 10.1016/j.euroneuro.2020.01.010

There is recent evidence that cocaine, nicotine, and their conditioned stimuli have the ability to enhance memory consolidation. The present study compared the effects of post-training heroin and of a heroin contextual conditioned stimulus (CS+) on consolidation of object recognition memory and investigated the roles of opioid and beta-adrenergic receptors in heroin/CS+ memory modulation by co-administering the respective antagonists, naltrexone (NTX) and propranolol (PRO). Three experiments were performed in male Sprague-Dawley rats demonstrating that immediate, but not delayed, post-sample exposure to heroin (0.3, 1 mg/kg), or exposure (30 min) to a contextual CS+ paired with 1 mg/kg heroin (5 pairings, each 120 min), equally enhanced object memory. Importantly, while the memory enhancing effects of 1 mg/kg heroin and of the contextual CS+ were not altered by post-training co-administration of 3 mg/kg naltrexone, they were blocked by post-training co-administration of 10 mg/kg propranolol. Taken together, these data suggest that a context paired with heroin shares the memory enhancing effect of heroin itself and that these unconditioned and conditioned drug stimuli may modulate memory through the activation of beta-noradrenergic receptors.