Biology subjects

Wemmie, J. A.

Publications and source records attributed to Wemmie, J. A..

5 recordsLinked to original sources

bioRxiv2026

Loss of ASIC1A-dependent inhibitory neuron activity in basolateral amygdala is associated with increased CO2-evoked jumping

BackgroundResponding appropriately to threats is critical for survival. Dysregulated defensive responses are core features of psychiatric illnesses including panic disorder and post-traumatic stress disorder. Carbon dioxide (CO2) inhalation evokes defensive behaviors in both humans and mice. Here we investigated the role of acid-sensing ion channels (ASICs) in CO2-evoked jumping in mice. MethodsDefensive behaviors (jumping and freezing) were assessed in response to CO2 inhalation and basolateral amygdala (BLA) acidification. We tested the role of ASICs using global knockout mice and Asic1aloxP/loxP mice transduced with AAV-CMV-Cre or AAV-CaMKII-Cre in the BLA. Effects of CO2 on single neuron firing and local field potentials were studied via BLA microwire arrays. ResultsASIC1A disruption increased CO2-evoked jumping while reducing freezing, paralleled by increased BLA c-Fos induction. Acidification of the BLA recapitulated these effects. Virus-mediated ASIC1A disruption in BLA did not resolve the locus of ASIC1A action in jumping. CO2 inhalation suppressed firing in most BLA neurons, though a small number increased firing. ASIC1A disruption enhanced CO2-induced suppression of narrow waveform neurons (putative interneurons), and facilitated excitation of wide waveform neurons (putative principal neurons). Additionally, CO2 produced concentration-dependent broadband power suppression with selective theta enhancement, effects that were augmented by ASIC1A disruption. ConclusionsTogether, these findings suggest that ASIC1A promotes interneuron activity during acidosis and that its loss may reduce inhibition of principal neuron output, shifting defensive responses from freezing toward jumping. These results advance our understanding of how brain pH and ASICs regulate defensive behavior, with potential implications for understanding dysregulated defensive responses.

neuroscience↗

bioRxiv2025

Carbonic anhydrase 4 disruption and pharmacological inhibition reduce synaptic and behavioral adaptations following oxycodone withdrawal

The ongoing opioid crisis underscores the need for innovative treatments targeting the neurobiological mechanisms underlying opioid-seeking behaviors and relapse. Here, we explored the role of carbonic anhydrase 4 (CA4) in modulating synaptic adaptations to oxycodone withdrawal in mice. We disrupted CA4 genetically and inhibited it pharmacologically with acetazolamide (AZD), a carbonic anhydrase inhibitor used clinically. We found that oxycodone withdrawal increased AMPAR/NMDAR ratio and synaptic recruitment of calcium-permeable AMPARs in nucleus accumbens core (NAcC) medium spiny neurons (MSNs). Synaptic changes required an extended period of abstinence, generalized to other opioids, including morphine and heroin, were more pronounced in D1 dopamine receptor-expressing MSNs, and were prevented by CA4 disruption. AZD administration in vitro and in vivo reversed the synaptic alterations, and the effects of AZD depended on CA4 and acid-sensing ion channel-1A. Interestingly, abstinence from oxycodone did not affect dendritic spine density in NAcC MSNs, in contrast to previously observed effects of abstinence from cocaine. Finally, in an oxycodone self-administration paradigm, CA4 disruption and AZD reduced drug-seeking behaviors following 30 days of forced abstinence. Together, these findings identify a critical role for CA4 in synaptic adaptations in opioid withdrawn mice and drug-seeking behavior. Moreover, they suggest pharmacological inhibitors of CA4 may hold therapeutic potential for reducing opioid-seeking and relapse in opioid use disorder.

neuroscience↗

bioRxiv2023

Cerebellar Morphological Differences in Bipolar Disorder Type I

BackgroundThe neural underpinnings of bipolar disorder (BD) remain poorly understood. The cerebellum is ideally positioned to modulate emotional regulation circuitry yet has been understudied in BD. Previous studies have suggested differences in cerebellar activity and metabolism in BD, however findings on cerebellar structural differences remain contradictory. MethodsWe collected 3T anatomical MRI scans from participants with (N = 131) and without (N = 81) BD type I. Differences in cerebellar volumes were assessed along with factors that influence the results. ResultsThe cerebellar cortex was smaller bilaterally in participants with BD. Polygenic propensity score (bipolar N = 103, control N = 64) did not predict any cerebellar volumes, suggesting that non-genetic factors may have greater influence on the cerebellar volume difference we observed in BD. Cerebellar white matter volumes increased with more adverse childhood events, but we did not observe any associations with parental psychiatric illness. We also evaluated time from onset and symptom burden and found no associations with cerebellar volumes, suggesting neurodevelopment may differ prior to onset. Finally, we found taking sedatives was associated with larger cerebellar white matter and non-significantly larger cortical volume. LimitationsThis study was cross-sectional, limiting interpretation of possible mechanisms. Most of our participants were White, which could limit the generalizability. Additionally, we did not account for potential polypharmacy interactions. ConclusionsThese findings suggest that external influences, such as medications, may influence cerebellum structure in BD and may mask underlying differences. Accounting for medication may be critical for consistent findings in future studies.

neuroscience↗

bioRxiv2023

Functional Connectivity of the Cerebellar Vermis in Bipolar Disorder and Associations with Mood

PurposeStudies of the neural underpinnings of bipolar type I disorder have focused on the emotional control network. However, there is also growing evidence for cerebellar involvement, including abnormal structure, function, and metabolism. Here, we sought to assess functional connectivity of the cerebellum with the cerebrum in bipolar disorder and to assess whether any effects might depend on mood. MethodsThis cross-sectional study enrolled 128 participants with bipolar type I disorder and 83 control comparison participants who completed a 3T MRI scan, which included anatomical imaging as well as resting state BOLD imaging. Functional connectivity of the cerebellar vermis to all other brain regions was assessed. Based on quality control metrics of the fMRI data, 109 participants with bipolar disorder and 79 controls were used to in the statistical analysis comparing connectivity of the vermis as well as associations with mood. Potential impacts of medications were also explored. ResultsFunctional connectivity of the cerebellar vermis in bipolar disorder was found to differ significantly between brain regions known to be involved in the control of emotion, motor function, and language. While connections with emotion and motor control areas were significantly stronger in bipolar disorder, connection to a region associated language production was significantly weaker. In the participants with bipolar disorder, ratings of depression and mania were inversely associated with vermis functional connectivity. No effect of medications on these connections were observed. ConclusionTogether the findings suggest cerebellum may play a compensatory role in bipolar disorder and when it can no longer fulfill this role, depression and mania develop. The proximity of the cerebellar vermis to the skull may make this region a potential target for treatment with transcranial magnetic stimulation.

neuroscience↗

bioRxiv2019

Loss of tau and Fyn reduces compensatory effects of MAP2 for tau and reveals a Fyn-independent effect of tau on glutamate-induced Ca2+ response

Microtubule-associated protein tau associates with Src family tyrosine kinase Fyn. A tau-Fyn double knockout (DKO) mouse was generated to investigate the role of the complex. DKO mice resembled Fyn KO in cognitive tasks and resembled tau KO mice in motor tasks and protection from pentylenetetrazole-induced seizures. In Ca2+ response, Fyn KO was decreased relative to WT and DKO had a greater reduction relative to Fyn KO, suggesting that tau may have a Fyn-independent role. Since tau KO resembled WT in its Ca2+ response, we investigated whether MAP2 served to compensate for tau, since its level was increased in tau KO but decreased in DKO mice. We found that like tau, MAP2 increased Fyn activity. Moreover, tau KO neurons had increased density of dendritic MAP2-Fyn complexes relative to WT neurons. Therefore, we hypothesize that in the tau KO, the absence of tau would be compensated by MAP2, especially in the dendrites, where tau-Fyn complexes are of critical importance. In the DKO, decreased levels of MAP2 made compensation more difficult, thus revealing the effect of tau in the Ca2+ response.\n\nSummary StatementThe downstream effect of the interaction between microtubule-associated protein tau and Src family non-receptor tyrosine kinase Fyn was investigated with a tau/Fyn double KO mouse. We demonstrate that tau has a Fyn-independent role in glutamate-induced calcium response and that MAP2 can compensate for tau in interacting with Fyn in dendrites.

neuroscience↗