Adrenalectomy attenuates the improvement of memory in rats by peripheral application of Des-Tyr-D-Pro4-casomorphin.
beta-Casomorphin derivatives without the N-terminal amino acid tyrosine possess memory-improving effects after central and peripheral application. We investigated the significance of adrenal glands for the memory improving effect of the systemically applied beta-casomorphin derivative des-Tyr-D-Pro4CM (Pro-Phe-D-Pro-Gly) in a learning experiment. Seven-week-old rats were adrenalectomized or sham operated. One week after surgery the rats were trained in an active avoidance task in a shuttle box. Five avoidance reactions were taken as learning criterion. After training 10 nmol/kg des-Tyr-D-Pro4CM or saline (10 ml/kg) was subcutaneously applied. There were no differences in acquisition between adrenalectomized and sham-operated rats. The memory retention of sham-operated animals was improved by des-Tyr-D-Pro4CM. In adrenalectomized rats this positive effect could not be observed. The involvement of adrenal glands in the peptide effect during learning and retention is discussed.
Rüthrich
H L
HL
Institute of Pharmacology and Toxicology, Medical Academy, Magdeburg, Germany.
Grecksch
G
G
Matthies
H
H
D000311:Adrenal Glands / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003213:Conditioning, Psychological / Q000187:drug effects; D004723:Endorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D004723:Endorphins; D010446:Peptide Fragments; C059556:beta-casomorphin, des-Tyr-