| First Author | Bouwknecht JA | Year | 2001 |
| Journal | Psychopharmacology (Berl) | Volume | 153 |
| Issue | 4 | Pages | 484-90 |
| PubMed ID | 11243496 | Mgi Jnum | J:103982 |
| Mgi Id | MGI:3610938 | Doi | 10.1007/s002130000598 |
| Citation | Bouwknecht JA, et al. (2001) Corticosterone responses in 5-HT1B receptor knockout mice to stress or 5-HT1A receptor activation are normal. Psychopharmacology (Berl) 153(4):484-90 |
| abstractText | RATIONALE: Previous research found no adaptations in presynaptic 5-HT1A receptors in mice lacking 5-HT1B receptors (5-HT1B KO). Stress and 5-HT1A receptor agonists induce corticosterone release in mice via hypothalamus-pituitary-adrenal (HPA) axis activation. 5-HT1B KO mice are hyperreactive to mild stressors and this might be reflected in altered postsynaptic 5-HT1A receptor sensitivity. OBJECTIVES: Our aim was to determine whether the activity of the HPA axis was increased in 5-HT1B KO mice in response to mild stress and pharmacological activation of 5-HT1A receptors as an indication of putative adaptive changes in postsynaptic 5-HT1A receptor function. METHODS: The effect of mild stress [i.e., the stress-induced hyperthermia (SIH) paradigm], induced by rectal temperature measurement, was determined on temperature and corticosterone over time (0, 5, 10, 20, 30, 60, and 90 min) in 5-HT1B KO and wildtype mice. In addition, corticosterone was measured 60 min after 5-HT1A receptor activation by flesinoxan (0, 0.03, 0.1, 0.3, 1, and 3 mg/kg s.c.). Blood was collected and plasma corticosterone levels were determined by radioimmunoassay. RESULTS: Both genotypes showed comparable time-dependent SIH responses, whereas basal temperature was higher in 5-HT1B KO mice. The effect of SIH on temperature was mirrored by mild increases in plasma corticosterone. Activation of 5-HT1A receptors caused a strong dose-dependent release of corticosterone in both genotypes. Neither response observed showed differences between both genotypes. CONCLUSIONS: Although 5-HT1B KO mice are hyperreactive to mild stress, this reactivity is not reflected by stronger corticosterone responses in the SIH paradigm. The lack of shift in dose-response curves for flesinoxan suggests that postsynaptic 5-HT1A receptor function is unaffected in 5-HT1B KO mice. |
