Article Figures & Data
Figures
- Figure 1.
Effects of l-theanine pre-exposure on social, cognitive, and depressive aberrations induced by adolescent THC exposure. A, Schematic representation of the social interaction apparatus. B, C, Chronic THC exposure did not influence social motivation (B) but induced significant deficits in social memory (C). l-theanine prevents the THC-induced impairments in social recognition (vehicle, n = 8; THC, n = 11; thea + THC, n = 12; theanine, n = 11; two-way ANOVA, post hoc Fisher's LSD; ***p < 0.001). D, Schematic protocol representation for object memory test. E, l-Theanine prevented THC-induced short-term memory impairments (vehicle, n = 10; THC, n = 11; thea + THC, n = 11; theanine, n = 10; two-way ANOVA, post hoc Fisher's LSD; ***p < 0.001). F, Schematic representation of the two-bottle sucrose preference test. G, l-Theanine prevented THC-induced anhedonia effects (vehicle, n = 8; THC, n = 11; thea + THC, n = 12; theanine, n = 11; two-way ANOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01).
- Figure 2.
Effects of l-theanine pre-exposure on affective and sensorimotor gating impairments induced by adolescent THC exposure. A, Schematic representation of light–dark box anxiety test. B, C, Adolescent THC-treated rats spent more time in the dark (B) and re-emerged later (C), indicating increased anxiety levels. l-Theanine administration partially prevents long-term THC-induced anxiety (vehicle, n = 10; THC, n = 12; thea + THC, n = 11; theanine, n = 8; two-way ANOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01). D, Schematic representation of PPI apparatus setup. E, Average startle amplitude response was not affected by any treatment. F, Compared with vehicle-treated controls, THC-treated rats exhibited impairments in sensory motor gating, which were fully prevented by l-theanine (vehicle, n = 8; THC, n = 11; thea + THC, n = 11; theanine, n = 8; two-way repeated-measures ANOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01, ***p < 0.001).
- Figure 3.
Effects of l-theanine exposure on adolescent THC-induced alterations of VTA DA and PFC pyramidal activity. A, l-Theanine prevents the subcortical hyperdopaminergic state induced by THC in terms of firing frequency. B, THC-treated rats exhibited an increase in bursting activity, which was not prevented by l-theanine + THC or l-theanine alone. Rats exposed to l-theanine alone showed a higher bursting activity when compared with the other groups (n = 36 cells from 6 vehicle rats; n = 26 cells from 5 THC rats; n = 41 cells from 4 thea + THC rats; n = 31 cells from 5 theanine rats; two-way ANCOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01, ***p < 0.001). C, Traces and rate histograms of representative VTA DA neurons recorded from each group. D, The firing rate of spontaneous PFC putative pyramidal neurons was not altered by adolescent THC treatment (n = 45 cells from 7 vehicle rats; n = 37 cells from 5 THC rats; n = 74 cells from 6 thea + THC rats; n = 40 cells from 5 theanine rats; two-way ANCOVA, post hoc Fisher's LSD; p > 0.05). E, However, the analysis of bursting activity revealed that l-theanine significantly prevented hyperbursting phenotypes induced by adolescent THC (n = 37 cells from 7 vehicle rats; n = 31 cells from 5 THC rats; n = 57 cells from 6 thea + THC rats; n = 20 cells from 5 theanine rats; two-way ANCOVA, post hoc Fisher's LSD; ***p < 0.001). F, Traces and rate histograms of representative PFC pyramidal neurons recorded from each group.
- Figure 4.
Effect of l-theanine on THC-induced abnormalities in spontaneous cortical gamma oscillations (30–80 Hz). A, Representative spectrogram of a 5 min recording during desynchronized state, characterized by small-amplitude fast oscillations (trace on the top). LFP power values between 59 and 61 Hz were excluded since they were reflecting the power line frequency. B, Average normalized power spectra representing LFP during the desynchronized state in prefrontal cortex of the four experimental groups. The THC-treated group displayed a decrease in total gamma oscillations (30–80 Hz) during the desynchronized state. l-Theanine prevented THC-induced abnormalities in prefrontal LFP gamma oscillations. C, Group summary comparing LFP power following adolescent treatments. The THC-induced reduction in the total power of gamma oscillations in the desynchronized state was fully prevented by pre-exposure to l-theanine (n = 20 recording sites from 6 vehicle rats; n = 17 recording sites from 3 THC rats; n = 23 recording sites from 4 thea + THC rats; n = 17 recording sites from 4 theanine rats; two-way ANCOVA, post hoc Fisher's LSD; *p < 0.05, ***p < 0.001).
- Figure 5.
Effects of l-theanine on the expression of THC-induced schizophrenia-like abnormalities in molecular biomarkers. A, Representative Western blots for phosphorylated and total GSK-3α and β expression (left) in the PFC. Densitometry analysis revealed that l-theanine reverts THC-induced decreases in both GSK-3 isoforms, α and β, and in the ratio of phosphorylated to total GSK-3α and GSK-3β (vehicle, n = 8; THC, n = 7; thea + THC, n = 8; theanine, n = 8; two-way ANOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01, ***p < 0.001). No differences were detected in total GSK-3α and GSK-3β (n = 8 for each group). B, Representative Western blots for phosphorylated and total AKT expression in PFC (top). l-Theanine coadministration normalized reductions in phosphorylated AKT-Thr308 and in the ratio of phosphorylated to total AKT-Thr308 induced by THC exposure during adolescence (vehicle, n = 8; THC, n = 7; thea + THC, n = 8; theanine, n = 8; two-way ANOVA, post hoc Fisher's LSD; *p < 0.05, **p < 0.01). No significant changes in phosphorylated AKT-Ser473 and in the ratio of phosphorylated to total AKT-Ser473 as well as in total AKT were detected (n = 8 for each group).
