Old rats are unresponsive to the behavioral effects of adrenocorticotropin.
In 28 month-old male rats, the i.c.v. injection of adrenocorticotropin [ACTH-(1-24)] (4 micrograms/rat) did not induce the typical behavioral syndrome (excessive grooming, stretching, yawning, penile erections). This indicates that the behavioral effects of melanocortins are age-dependent, suggesting either an aging-linked impairment of the nervous circuitries involved or a reduction of the number (or affinity, or both) of the brain melanocortin receptors in the elderly.
Poggioli
R
R
Department of Biomedical Sciences, Section of Pharmacology, University of Modena, Italy.
Benelli
A
A
Arletti
R
R
Vergoni
A V
AV
Menozzi
B
B
Bertolini
A
A
D000375:Aging / Q000523:psychology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003366:Cosyntropin / Q000494:pharmacology*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D010446:Peptide Fragments; D003366:Cosyntropin; D009074:Melanocyte-Stimulating Hormones