Supplementary Materials Appendix EMMM-12-e10605-s001. are still present 2?weeks after the same treatments delivered at the adult stage. Collectively, these findings suggest a role of 5\HT 6 receptor\operated mTOR signaling in abnormalities of cortical network wiring elicited by THC at a critical period of PFC maturation and highlight the potential of 5\HT 6 receptor antagonists as early therapy to prevent cognitive symptom onset in adolescent cannabis abusers. test. n.s.: not significant. B Wild\type mice were injected daily with THC (5?mg/kg) or vehicle (Veh) during adolescence, from PND 30 to 45. CPPQ (2.5?mg/kg) was administered concomitantly with vehicle or THC. Top: representative Western blots assessing mTOR phosphorylation at S2448 and p70S6K phosphorylation at T389 as indexes of mTOR activity in the PFC of adult WT mice are illustrated. Bottom: data represent the ratios of immunoreactive signals of the anti\phospho\mTOR (S2448) or anti\phospho\P70S6K (T389) antibodies to the immunoreactive signal of the anti\\actin antibody and are expressed in % of values in vehicle\injected mice. They are the means??SEM of results obtained in three mice per group. test. 5HT6 receptors are known to exhibit a high level of constitutive activity both and (Kohen test. Time spent in the center: 19.18??1.69% and 20.39??1.22% for vehicle (test. Errors bars correspond to the mean??SEM. B Percentage of open arm time and entries in the EPM. Time spent in the open arm: 23.24??3.25% and 18.86??3.45% for vehicle (test. n.s.: not significant. Number of entries in the open arm: 15??1 entries and 11??2 entries for vehicle (test. Errors bars correspond to the mean??SEM. Given the deleterious influence of non\physiological mTOR activation upon cognition in various neuropsychiatric conditions (Hoeffer & Klann, 2010; Bockaert & Marin, 2015) and its role in cognitive deficits induced purchase AdipoRon by cannabis intake, we next explored whether blocking 5\HT6 receptor\elicited mTOR elevation in adolescent mice IL12RB2 exposed to THC prevents the associated cognitive impairments in adulthood. THC\injected mice treated with SB258585 or rapamycin during adolescence showed a similar performance as vehicle\injected animals in the novel object recognition task (discrimination index: 0.45??0.07, (daily injections from PND 60 to 75). Biochemical analysis and purchase AdipoRon behavioral studies were performed 2?weeks after the last injection of the 5\HT6 receptor antagonist or rapamycin (PND 90, Fig?3A). A significant increase in phosphorylated mTOR and p70S6K was observed at PND 90 in THC\injected mice, compared with vehicle\injected mice, and this mTOR overactivation was not affected by SB258585 or rapamycin administration at the adult stage (Fig?3B). Moreover, performances were comparable in the THC\injected mice treated or not with SB258585 or rapamycin in adulthood in purchase AdipoRon the novel object recognition task (Fig?3C). These results demonstrate that blocking the 5\HT6/mTOR signaling pathway at the adult stage in mice injected with THC during adolescence does not abolish the long\lasting activation of mTOR and, consequently, does not induce continual cognitive improvements. Open up in another window Body 3 THC\induced lengthy\long lasting mTOR activation and cognitive deficits aren’t inhibited with the administration of SB258585 or rapamycin in adulthood A Schema from the experimental paradigm useful for medication administration. Mice had been injected daily with THC (5?mg/kg) or automobile (Veh) during adolescence, from PNDs 30 to 45. Automobile and THC\injected mice had been treated daily with either automobile or SB258585 (SB, 2.5?mg/kg) or rapamycin (Rapa, 1.5?mg/kg) from PNDs 60 to 75. Biochemical and behavioral tests had been performed from PND 90. B Best: representative American blots evaluating mTOR activity in PFC are illustrated. Bottom level: data represent the ratios of immunoreactive indicators from the anti\phospho\mTOR (S2448) or anti\phospho\p70S6K (T389) antibodies towards the immunoreactive signal of the anti\\actin antibody and are expressed in % of values in vehicle\injected mice. They are the means??SEM of results obtained in six mice per group. *test. RMP: ?68.4??2.0 and ?68.3??1.2?mV for Veh/CPPQ and THC/CPPQ, respectively; AP threshold: ?33.9??2.0 and ?34.2??0.9?mV for Veh/CPPQ and THC/CPPQ conditions, respectively; Rheobase: 644??66 and 574??48 pA for Veh/CPPQ and THC/CPPQ conditions, respectively. Hyperpolarization\activated cyclic nucleotide\gated channel 1 (HCN1) is the predominant isoform of HCN channels, a family of voltage\gated ion channels responsible for the hyperpolarization\activated current (during the adolescence period, but not by the 5\HT6 receptor blockade at the adult stage. The latter observation indicates it might result from a non\physiological 5\HT6 receptor activation by endogenously released 5\HT rather than constitutive activity, which might be caused by CB1 receptor\mediated decrease in GABA release and the disinhibition of 5\HT terminals (Fig?7) in the.