PKCδ Knockout Mice Are Protected from Dextromethorphan-Induced Serotonergic Behaviors in Mice: Involvements of Downregulation of 5-HT1A Receptor and Upregulation of Nrf2-Dependent GSH Synthesis

Abstract

We investigated whether a specific serotonin (5-HT) receptor-mediated mechanism was involved in dextromethorphan (DM)-induced serotonergic behaviors. We firstly observed that the activation of 5-HT receptor, but not 5-HT receptor, contributed to DM-induced serotonergic behaviors in mice. We aimed to determine whether the upregulation of 5-HT receptor induced by DM facilitates the specific induction of certain PKC isoform, because previous reports suggested that 5-HT receptor activates protein kinase C (PKC). A high dose of DM (80 mg/kg, i.p.) induced a selective induction of PKCδ out of PKCα, PKCβI, PKCβII, PKCξ, and PKCδ in the hypothalamus of wild-type (WT) mice. More importantly, 5-HT receptor co-immunoprecipitated PKCδ in the presence of DM. Consistently, rottlerin, a pharmacological inhibitor of PKCδ, or PKCδ knockout significantly protected against increases in 5-HT receptor gene expression, 5-HT turnover rate, and serotonergic behaviors induced by DM. Treatment with DM resulted in an initial increase in nuclear factor erythroid-2-related factor 2 (Nrf2) nuclear translocation and DNA-binding activity, γ-glutamylcysteine (GCL) mRNA expression, and glutathione (GSH) level. This compensative induction was further potentiated by rottlerin or PKCδ knockout. However, GCL mRNA and GSH/GSSG levels were decreased 6 and 12 h post-DM. These decreases were attenuated by PKCδ inhibition. Our results suggest that interaction between 5-HT receptor and PKCδ is critical for inducing DM-induced serotonergic behaviors and that inhibition of PKCδ attenuates the serotonergic behaviors via downregulation of 5-HT receptor and upregulation of Nrf2-dependent GSH synthesis.

Lithium attenuates d‐amphetamine‐induced hyperlocomotor activity in mice via inhibition of interaction between cyclooxygenase‐2 and indoleamine‐2,3‐dioxygenase

“…Western blotting analysis was performed as previously described . Proteins (20 μg/lane) were separated by 10% sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and transferred onto polyvinylidene fluoride (PVDF) membranes.…”

“…Western blotting analysis was performed as previously described. 64,65 Proteins (20 μg/lane) were separated by 10% sodium dodecyl sulfate- and IDO-2 have been described in previous reports. 21,66 After washing in PBS, the membranes were incubated with horseradish peroxidase (HRP)-conjugated secondary anti-rabbit immunoglobulin (IgG; 1:5000; Thermo Scientific), anti-goat immunoglobulin (IgG; 1:5000; Thermo Scientific), or anti-mouse IgG (1:5000; Sigma-Aldrich) for 2 hours.…”

Ginsenoside Re Protects against Serotonergic Behaviors Evoked by 2,5-Dimethoxy-4-iodo-amphetamine in Mice via Inhibition of PKCδ-Mediated Mitochondrial Dysfunction

“…We recently demonstrated that hypothalamic PKCδ levels might play a critical role in inducing serotonin behaviors [35,54,55]. As shown in Figure 1 of the experimental design, we investigated whether GRe, the PKCδ inhibitor rottlerin, or the 5-HT 2A receptor antagonist MDL affects the mitochondrial translocation of PKCδ induced by the 5-HT 2A agonist DOI.…”

“…We [13,[41][42][43][44][45][46][47][48][49] and others [50][51][52][53] have suggested that PKC is important for neuropsychotoxicity induced by amphetamine and its analogues. In particular, the PKCδ gene is a crucial target for generating serotonergic behaviors [35,54].…”

Clozapine attenuates mitochondrial burdens and abnormal behaviors elicited by phencyclidine in mice via inhibition of p47phox; Possible involvements of phosphoinositide 3-kinase/Akt signaling

“…Immunoprecipitation was performed as described previously (Tran et al, 2018) using protein G-sepharose (GE Healthcare, Piscataway, New Jersey, USA). Prefrontal cortical tissues were homogenized in lysis buffer for 1 min on ice and centrifuged at 12,000×g for 20 min at 4°C to remove particulate matter.…”