Sub-chronic cold stress reduces 5-HT1A receptor responsiveness in the old but not in the young rat

• Published in: Neuroscience letters 1996-01, Vol.203 (1), p.21-24
• Main Authors: DE CASTRO, R. M, BOLANOS-JIMENEZ, F, SEGUIN, L, SARHAN, H, DRIEU, K, FILLION, G
• Format: Article
• Language: English
• Subjects: 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; Aging - metabolism; Animals; Biological and medical sciences; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Cold Temperature; Cyclic AMP - metabolism; Dose-Response Relationship, Drug; Fundamental and applied biological sciences. Psychology; Hippocampus - drug effects; Life Sciences; Male; Neurons and Cognition; Rats; Rats, Wistar; Receptors, Serotonin - drug effects; Receptors, Serotonin - physiology; Stress, Physiological - physiopathology; Vertebrates: nervous system and sense organs
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/0304-3940(95)12253-2

The inhibitory effect of the prototypical 5-hydroxytryptamine (5-HT)1A receptor agonist 8-hydroxy-2-(di-n-propyl amino)tetraline (8-OH-DPAT) on forskolin-stimulated adenylyl cyclase activity, has been examined as an index of the functional activity of 5-HT1A receptors in the hippocampus of young (3 months) and old (18 months) rats exposed during 24 h or 5 days to cold. In both young and old rats exposed to cold stress during 24 h, there was a reduction in the potency (EC50) and/or the maximal inhibitory effect (Emax) of 8-OH-DPAT in reducing forskolin-induced cAMP accumulation. The properties of the hippocampal 5-HT1A sites labelled by [3H]8-OH-DPAT were not affected by these stressful conditions. Moreover, while the sensitivity of 5-HT1A receptors to 8-OH-DPAT in young rats returned to control values after 5 days of cold exposure, old rats still exhibited a significant desensitization of 5-HT1A receptors as compared to naive animals. These results point out the capacity of young but not of old rats to adapt to the aversive effects of a subchronic stressor.