Biology subjects

Chaudhari, P. R.

Publications and source records attributed to Chaudhari, P. R..

5 recordsLinked to original sources

bioRxiv2026

Serotonin2A receptors in the medial prefrontal cortex do not drive DOI-induced head-twitch responses in rodents

Background The head-twitch response (HTR) is a serotonin2A receptor (5-HT2AR) dependent behavioral correlate of serotonergic psychedelic action in rodent models. Although cortical 5-HT2ARs have been implicated in HTRs, the contribution of specific cortical circuits to this behavior remains poorly defined, with a few reports implicating the medial prefrontal cortex (mPFC) in the generation of HTRs. Results The serotonergic psychedelic, 2,5-dimethoxy-4-iodoamphetamine (DOI), induced head-twitch responses (HTRs) in male and female rats and mice, with sex differences noted only in mice. DOI also increased ear-scratch responses (ESRs), and reduced digging and grooming behaviors only in mice. While the DOI-evoked HTRs and ESRs were absent in 5-HT2AR knock-out (5-HT2AR KO) mice, reduced digging and grooming occurred in both wild-type and 5-HT2AR KO mice. We assessed the role of 5-HT2ARs in the mPFC in regulating DOI-induced HTRs using pharmacological and genetic approaches. Targeted DOI microinfusion into the mPFC did not induce HTRs in rats, in contrast to the robust increase in HTRs noted following systemic DOI administration. Local delivery of the selective 5-HT2AR antagonist, MDL100907, into the mPFC also had no effect on the systemic DOI-evoked increase in HTRs in rats. Experiments capitalizing on genetic strategies to perturb 5-HT2AR expression in the mPFC, indicated that viral restoration of 5-HT2AR expression in mPFC CaMKII-positive excitatory neurons was not sufficient to reinstate DOI-evoked HTRs or ESRs in 5-HT2AR KO mice. Further, conditional 5-HT2AR deletion in CaMKII-positive excitatory neurons in the mPFC did not alter systemic DOI-induced HTRs and ESRs in mice. Conclusions These findings indicate that the serotonergic psychedelic DOI induces species- and sex-specific behavioral effects in rodent models, with a robust 5-HT2AR dependence noted for DOI-evoked HTRs and ESRs. Further, we show that 5-HT2ARs in the mPFC do not appear to contribute to the enhanced HTRs and ESRs elicited by DOI.

neuroscience↗

bioRxiv2026

Early-life stress-induced gut dysbiosis is ameliorated by nicotinamide treatment

Early life stress (ELS) in the form of adverse experiences in childhood results in multiple psycho-physiological pathologies during adulthood and accelerates aging. Such pathologies are recently observed to be alleviated upon nicotinamide treatment in a maternal separation model of ELS. We report a nicotinamide-driven amelioration of gut dysbiosis in middle-aged rodents with a history of neonatal maternal separation.

microbiology↗

bioRxiv2026

Chronic postnatal chemogenetic activation of forebrain excitatory neurons modulates adult glial function and metabolism in male mice

Early adversity increases vulnerability for adult psychopathology. Across multiple pre-clinical models of early adversity, there are reports of glial dysfunction and disrupted amino acid neurotransmission, along with maladaptive behavioral responses in adulthood. Disrupted G-protein coupled receptor signaling is known to phenocopy specific consequences of early life adversity. Enhanced Gq signaling in the forebrain excitatory neurons in early postnatal life programs anxio-depressive behaviors in adulthood, accompanied by altered neuronal glutamate and GABA metabolism in mouse models. We hypothesized that enhancing Gq signaling in forebrain excitatory neurons in early postnatal life may also impact glial function in adulthood. Our results show that postnatal hM3Dq-mediated chemogenetic activation of CaMKII-positive forebrain excitatory neurons not only increases anxiety-like behavior, but also evokes bidirectional transcriptional regulation of multiple glia-associated genes in the neocortex and hippocampi. While Gfap, Aldh1l1, S100{beta}, Eaat1, Eaat2 and Eaat3, mRNA levels were reduced in the neocortex, they were enhanced in the hippocampus, and a similar pattern was noted for GFAP protein levels. Transient, postnatal chemogenetic activation of CaMKII-positive neurons did not alter astrocyte cell density in both the neocortex and the hippocampus. Using (1H-(13C)) NMR spectroscopy, we observed a significant decline in astrocyte-specific glutamate and GABA neurotransmitter turnover, and a reduction in astrocyte metabolic flux within the neocortex and the hippocampus in adulthood in animals with a history of postnatal chemogenetic activation of forebrain excitatory neurons. Our findings indicate that chemogenetically driving Gq signaling transiently during the postnatal window in forebrain excitatory neurons results in persistent changes well into adulthood, with enhanced anxiety-like behaviors and disrupted glial function and metabolism, phenocopying specific changes in glial function noted following early adversity.

neuroscience↗

bioRxiv2021

Chronic hM4Di-DREADD mediated chemogenetic inhibition of forebrain excitatory neurons in postnatal or juvenile life does not alter adult mood-related behavior

G-protein coupled receptors (GPCRs) coupled to Gi-signaling, in particular downstream of monoaminergic neurotransmission, are posited to play a key role during developmental epochs (postnatal and juvenile), in shaping the emergence of adult anxio-depressive behaviors and sensorimotor gating. To address the role of Gi-signaling in these developmental windows, we used a CamKII-tTA::TRE hM4Di bigenic mouse line to express the hM4Di-DREADD in forebrain excitatory neurons and enhanced Gi-signaling via chronic administration of the DREADD agonist, CNO in the postnatal (PNCNO: postnatal day 2-14) or juvenile (JCNO: postnatal day 28-40) window. We confirmed that the expression of the HA-tagged hM4Di-DREADD was restricted to CamKII-positive neurons in the forebrain, and administration of CNO in postnatal or juvenile windows evoked inhibition in forebrain circuits of the hippocampus and cortex, as indicated by a decline in expression of the neuronal activity marker, c-fos. hM4Di-DREADD mediated inhibition of CamKII-positive forebrain excitatory neurons in postnatal or juvenile life did not impact the weight profile of mouse pups, and also did not influence the normal ontogeny of sensory reflexes. Further, postnatal or juvenile hM4Di-DREADD mediated inhibition of CamKII-positive forebrain excitatory neurons did not alter anxiety or despair-like behaviors in adulthood, and did not impact sensorimotor gating. Collectively, these results indicate that chemogenetic induction of Gi-signaling in CamKII-positive forebrain excitatory neurons in postnatal and juvenile temporal windows does not appear to impinge on the programming of anxio-depressive behaviors in adulthood.

neuroscience↗

bioRxiv2020

Chronic chemogenetic activation of forebrain excitatory neurons in postnatal life evokes long-lasting changes in mood-related behavior

Early adversity is a key risk factor for the development of adult psychopathology, including anxiety, depression and schizophrenia. Rodent models of early adversity program persistent behavioral, molecular, metabolic, and neurophysiological changes. Perturbed signaling via forebrain Gq-coupled neurotransmitter receptors is a common feature across multiple models of early adversity. We addressed whether enhanced Gq-mediated signaling in forebrain excitatory neurons during postnatal life can evoke long-lasting mood-related behavioral changes. Excitatory hM3Dq DREADD-mediated chemogenetic activation of CamKII-positive forebrain excitatory neurons during postnatal life (P2-14) increased anxiety- and despair-like behavior, and evoked sensorimotor gating deficits in adulthood. In contrast, chronic chemogenetic hM3Dq DREADD activation of forebrain excitatory neurons in the juvenile or adult window did not evoke any mood-related behavioral alterations, highlighting the criticality of the postnatal temporal window. The enhanced anxiety-, despair- and schizophrenia-like behavioral changes evoked by chronic chemogenetic activation of forebrain excitatory neurons in postnatal life, was accompanied by an increased cortical and hippocampal metabolic rate of glutamatergic and GABAergic neurons in adulthood. Furthermore, animals with a history of postnatal hM3Dq activation exhibited a decline in the expression of activity-dependent and plasticity-associated markers within the hippocampus, along with perturbed hippocampal excitatory and inhibitory currents in adulthood. These results indicate that Gq signaling mediated activation of forebrain excitatory neurons during the critical postnatal window is sufficient to program altered mood-related behavior, as well as metabolic and neurophysiological changes in forebrain glutamate and GABA systems, recapitulating specific aspects of the consequences of early adversity.

neuroscience↗