Biology subjects

Rantamäki, T.

Publications and source records attributed to Rantamäki, T..

3 recordsLinked to original sources

bioRxiv2026

Molecular signaling associated with antidepressant actions exhibits diurnal fluctuations in the prefrontal cortex and hippocampus of adult male and female mice

An increasing number of epidemiological and experimental studies have demonstrated a bidirectional relationship between mood disorders and the circadian system, with disrupted circadian rhythms contributing to depressive states, and their restoration playing a key role in antidepressants effects. In this context, we sought to examine whether key molecular targets of antidepressants exhibit diurnal regulatory patterns. Naive adult male and female C57BL/6 mice were euthanized at 3-hour intervals beginning at Zeitgeber Time 0 (ZT0), and hippocampal (HC) and medial prefrontal cortex (mPFC) tissues were collected for RT-qPCR and western blot analyses. We observed statistically significant diurnal rhythmicity in all analyzed transcripts (cFos, Arc, Nr4a1, Dusp1, Dusp5, and Dusp6) in both HC and mPFC samples, with peak expression occurring during the dark (active) phase (ZT15-18). Phosphorylation levels of TrkBY816 (tropomyosin-related kinase) and GSK3{beta}S9 (glycogen synthase kinase 3{beta}) also showed periodic rhythmicity, peaking during the light (inactive) phase. Levels of p-ERK2T185/Y187 (extracellular-signal regulated kinase) did not display rhythmicity, but peaked during the light phase in the HC, especially in males. Collectively, these findings demonstrate that antidepressant targets are subject to diurnal regulation, highlighting the importance of integrating circadian biology and time-of-day as relevant variables in the development of translationally relevant antidepressant research. HighlightsO_LIKey molecular targets of antidepressants exhibit diurnal regulation in adult mice C_LIO_LIDiurnal patterns were conserved across targets, sexes, and brain regions (HC&PFC) C_LIO_LIcFos, Arc, Nr4a1, Dusp1,5,6 mRNAs display peak expression during the dark phase C_LIO_LITrkBY816 and GSK3{beta}S9 phosphorylation peak during the light (inactive) phase C_LIO_LIAntidepressant mechanisms may be linked with circadian and sleep-wake dynamics C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/716906v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1e65e60org.highwire.dtl.DTLVardef@13e302corg.highwire.dtl.DTLVardef@1ccc25forg.highwire.dtl.DTLVardef@1ed10d3_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Rapid-acting antidepressants ketamine and nitrous oxide converge on MAPK-DUSP signaling in the medial prefrontal cortex

Nitrous oxide (N2O; laughing gas) has recently been reported as a putative rapid-acting antidepressant, but little is known about the underlying mechanisms. We performed transcriptomics, in situ hybridization, and electrophysiological studies to examine the potential shared signatures induced by 1 h inhalation of 50% N2O and a single subanesthetic dose of ketamine in the medial prefrontal cortex (mPFC) in adult mice. Both treatments similarly affected the transcription of several negative regulators of mitogen-activated protein kinases (MAPKs), namely, dual specificity phosphatases. The effects were primarily located in the pyramidal cells. Notably, the overall effects of N2O on mRNA expression were much more prominent and widespread compared to ketamine. Ketamine caused an elevation of the spiking frequency of putative pyramidal neurons and increased gamma activity (30-100 Hz) of cortical local field potentials. However, N2O produced no such effects. Spiking amplitudes and spike-to-local field potential phase locking of putative pyramidal neurons and interneurons in this brain area showed no uniform changes across treatments. Thus, this study characterized the electrophysiological and transcriptome-wide changes in mPFC triggered by exposure to N2O and compared them with those caused by the rapid-acting antidepressant ketamine in terms of both the direction of their regulation and localization.

pharmacology and toxicology↗

bioRxiv2018

Putative rapid-acting antidepressant nitrous oxide ("laughing gas") evokes rebound emergence of slow EEG oscillations during which TrkB signaling is induced

Electroconvulsive therapy (ECT) remains among the most efficient antidepressants but it seldom brings immediate remedy. However, a subanesthetic dose of NMDA-R (N-methyl-D-aspartate receptor) blocker ketamine ameliorates symptoms of depression already within hours. Glutamatergic excitability and regulation of TrkB neurotrophin receptor and GSK3{beta} (glycogen synthase kinase 3{beta}) signaling are considered as molecular-level determinants for ketamines antidepressant effects. Recent clinical observations suggests that nitrous oxide (N2O, \"laughing gas\"), another NMDA-R blocking dissociative anesthestic, also produces rapid antidepressant effects but the underlying mechanisms remain essentially unstudied. In this animal study we show that N2O, with a clinically relevant dosing regimen, evokes an emergence of rebound slow EEG (electroencephalogram) oscillations, a phenomenon considered to predict the efficacy and onset-of-action ECT. Very similar rebound slow oscillations are induced by subanesthetic ketamine and flurothyl (a treatment analogous to ECT). These responses become best evident upon drug withdrawal, i.e. after the peak of acute pharmacological actions, when their most prominent effects on cortical excitability have subsided. Most importantly, TrkB and GSK3{beta} signaling remain unchanged during N2O administration (ongoing NMDA-R blockade) but emerge gradually upon gas withdrawal along with increased slow EEG oscillations. Collectively these findings reveal that rapid-acting antidepressants produce cortical excitability that triggers \"a brain state\" dominated by ongoing slow oscillations, sedation and drowsiness during which TrkB and GSK3{beta} signaling alterations are induced.

pharmacology and toxicology↗