Fig. 4.
Chronic administration of the 5-HT2A antagonist ketanserin (Ket) but not altanserin (Alt) down-regulates the cortical 5-HT2A receptor level in C57BL/6J mice. A, measurement of 5-HT2A receptor level in frontal cortex membrane lysates by immunoblotting (IB) of immunoprecipitates (IP). The same blots were reprobed for transferrin receptor as loading controls. B, densitometry of immunoblots of immunoprecipitates from n = 4 mice/treatment group. *, p < 0.05, unpaired t test. C, Bmax estimates were obtained by performing [3H]ketanserin saturation binding on cortical membrane homogenates. Data are presented as mean ± S.E.M. (n = 6/group). D–F, chronic treatment with vehicle or ketanserin or altanserin (10.0 mg/kg, 14 days) had no significant effect on PCP (6.0 mg/kg)-induced hyperactivity in C57BL/6J mice (n = 8/group). Data are expressed as mean total horizontal distance traveled in 5-min bins over 90 min after PCP administration (±S.E.M.). MW, molecular weight; Veh, vehicle.