title: Stress-dependent impairment of passive-avoidance memory by propranolol or naloxone.
abstract: Previous work has shown that the effect of opioid-receptor blockade on memory modulation is critically dependent upon the intensity of stress. The current study determined the effect of adrenergic-receptor blockade on memory modulation under varied levels of stress and then compared the effect of adrenergic-receptor blockade under intense stress to that of a) opioid-receptor blockade and b) concurrent opioid- and adrenergic-receptor blockade. In the first experiment, the β-adrenergic-receptor blocker propranolol impaired retention in the passive-avoidance procedure when administered immediately after exposure to intense stress (passive-avoidance training followed by swim stress) but not mild stress (passive-avoidance training alone). In the second experiment, while separate administration of either propranolol or the opioid-receptor blocker naloxone immediately after exposure to intense stress impaired retention, the combined administration of propranolol and naloxone failed to do so. These findings demonstrate that the effect of β-adrenergic-receptor blockade or opioid-receptor blockade on memory modulation in the passive-avoidance procedure is dependent upon the intensity of stress, and suggest that concurrent inactivation of endogenous adrenergic- and opioid-based memory modulation systems under stressful conditions is protective of memory.
authors.affiliation: Department of Psychology, Swarthmore College, Swarthmore, PA 19081, United States. ASchnei1@Swarthmore.edu
authors.forename: Allen M
authors.initials: AM
authors.lastname: Schneider
authors.forename: Peter E
authors.initials: PE
authors.lastname: Simson
authors.forename: Ranga K
authors.initials: RK
authors.lastname: Atapattu
authors.forename: Lynn G
authors.initials: LG
authors.lastname: Kirby
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology; D012153:Retention, Psychology / Q000187:drug effects / Q000502:physiology; D013312:Stress, Physiological
chemical_list: D000319:Adrenergic beta-Antagonists; D009292:Narcotic Antagonists; D011943:Receptors, Adrenergic, beta; D011957:Receptors, Opioid; D009270:Naloxone; D011433:Propranolol