Biology subjects

Briones, A.

Publications and source records attributed to Briones, A..

2 recordsLinked to original sources

bioRxiv2026

Projection-defined ventral tegmental area neurons exhibit distinct molecular adaptations during acute fentanyl withdrawal

Opioid use disorder (OUD) remains a major public health concern, with potent synthetic opioids driving overdose deaths. Understanding how synthetic opioids like fentanyl alter brain circuits to promote persistent use is critical for advancing OUD treatment. The ventral tegmental area (VTA), which projects to several other brain regions including prefrontal cortex (PFC), nucleus accumbens (NAc) and amygdala (Amy), contributes to both the euphoric and dysphoric phases of OUD. Projection target influences the baseline properties and opioid-induced neuroadaptations of VTA neurons, yet less is known about the molecular adaptations that occur across distinct VTA projections during spontaneous opioid withdrawal. Here, we investigated transcriptional responses to acute spontaneous fentanyl withdrawal in projection-defined VTA neurons. Following chronic fentanyl exposure and 24h of spontaneous withdrawal in male and female mice, we sequenced ribosome-associated RNA from VTA neurons projecting to PFC, NAc, or Amy. We found that fentanyl withdrawal produced divergent transcriptional adaptations in VTA neurons projecting to PFC compared with VTA-NAc and VTA-Amy neurons, whereas adaptations in VTA-NAc and VTA-Amy neurons were more concordant. Weighted gene co-expression network analysis (WGCNA) identified fentanyl-responsive modules across VTA projections, with gene ontology analysis linking these modules to distinct biological processes. We further used regulatory enrichment analysis to identify candidate transcriptional regulators associated with fentanyl-responsive co-expression modules. Together, our data demonstrate that VTA neurons undergo distinct molecular adaptations during fentanyl withdrawal based on their projection target, providing new insight into molecular mechanisms relevant to OUD.

neuroscience↗

bioRxiv2022

Extinction risk, reconstructed catches, and management of chondrichthyan fishes in the Western Central Atlantic Ocean

Chondrichthyan fishes are among the most threatened vertebrates on the planet because many species have slow life histories that are outpaced by intense fishing. The Western Central Atlantic Ocean, which includes the greater Caribbean, is a hotspot of chondrichthyan biodiversity and abundance, but is historically characterized by extensive shark and ray fisheries and a lack of sufficient data for effective management and conservation. To inform future research and management decisions, we analyzed patterns in chondrichthyan extinction risk, reconstructed catches, and regulations in this region. We summarized the extinction risk of 180 sharks, rays, and chimaeras using contemporary IUCN Red List assessments and found that over one-third (35.6%) were assessed as Vulnerable, Endangered, or Critically Endangered largely due to fishing. Reconstructed catches from 1950 to 2016 reached their peak in 1992, then declined by 40.2% through the end of the series. The United States, Venezuela, and Mexico were responsible for most catches and hosted large proportions of the regional distributions of threatened species; these countries therefore held the greatest responsibility for chondrichthyan management. The abundance and resolution of fisheries landings data were poor in much of the region, and national-level regulations varied widely across jurisdictions. Deepwater fisheries represent an emerging threat, although many deepwater chondrichthyans currently find refuge beyond the depths of most fisheries. Regional collaboration as well as effective and enforceable management informed by more complete fisheries data, particularly from small-scale fisheries, are required to protect and recover threatened species and ensure sustainable fisheries.

ecology↗