Inhibitory avoidance impairments induced by intra-amygdala propranolol are reversed by glutamate but not glucose.
Both systemic and central injections of glucose can enhance memory. For example, glucose reverses impairments on inhibitory avoidance resulting from intra-amygdala injections of morphine. The present experiment investigated the ability of glucose to reverse memory impairments resulting from intra-amygdala injections of propranolol, a beta-noradrenergic antagonist. Pretraining administration of 10 microg propranolol significantly reduced inhibitory avoidance retention latencies but had no effect on performance in a spontaneous alternation task. Coadministration of glucose into the amygdala at 3 doses (1.5, 3.0, and 6.0 microg) did not reverse the propranolol-induced inhibitory avoidance deficits. However, coadministration of 2.5 microg of glutamate with the propranolol did reverse these deficits. The ability of glucose to reverse impairments following intra-amygdala injections of morphine but not propranolol may reflect the neurotransmitter system or systems through which glucose exerts its effects.
Lennartz
R C
RC
Department of Psychology, University of Virginia, Charlottesville 22903, USA.
Hellems
K L
KL
Mook
E R
ER
Gold
P E
PE
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000679:Amygdala / Q000187:drug effects*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D005950:Glucose Solution, Hypertonic / Q000494:pharmacology*; D018698:Glutamic Acid / Q000494:pharmacology*; D007267:Injections; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects*; D017288:Pain Threshold / Q000187:drug effects; D011433:Propranolol / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D005950:Glucose Solution, Hypertonic; D018698:Glutamic Acid; D011433:Propranolol