1 8-Hydroxy-2-(di-n-propylamino)tetralin dose-dependently induced hypothermia in mice.2 The 5-HTIA receptor partial agonists, buspirone, gepirone and ipsapirone, also dose-dependently induced hypothermia. 6 Chronic antidepressant treatment down-regulated this 8-OH-DPAT response. In addition, chronic administration of anxiolytics and neuroleptics was also effective in this respect. Down-regulation was also observed following repeated administration of 8-OH-DPAT (0.5 mg kg-', s.c.), (± )-pindolol (10mg kg-', i.p.) and ketanserin (0.5 mg kg-', i.p.).7 In conclusion, these data confirm that 8-OH-DPAT-induced hypothermia is mediated by 5-HTIA autoreceptors. They also indicate that the response involves D2 receptors. The present study also shows that a wide range of antidepressant drugs down-regulate this response although this property is not restricted to antidepressant treatments. Therefore, care should be exercised when interpreting data from this paradigm.