Biology subjects

Nowlan, A. C.

Publications and source records attributed to Nowlan, A. C..

4 recordsLinked to original sources

bioRxiv2024

Diversity of ancestral brainstem noradrenergic neurons across species and multiple biological factors

The brainstem cell group, locus coeruleus (LC), is present across vertebrates and influences cardiorespiratory, metabolic, immune, and cognitive functions by activating in two putatively distinct firing patterns. Yet, the degree to which the LC firing rates and patterns are homogenous across species has never been assessed due to inherently limited sample sizes. To remedy this, we pooled cross-species data from 20 laboratories to show that firing rates differ across species and are modulated by sex, age, and type of in vitro or in vivo preparation. Contrary to the prevailing dual-mode firing pattern schema, we observed patterns spread across a low-dimensional manifold, with subregions enriched for specific biological factors and neurodegenerative disease models. Our findings show considerable diversity in an ancestral vertebrate neuromodulatory system.

neuroscience↗

bioRxiv2023

Xylazine is an agonist at kappa opioid receptors and exhibits sex-specific responses to naloxone administration

Xylazine has been found in the unregulated drug supply at increasing rates, usually in combination with fentanyl. It has become critical to understand its basic pharmacology, how it impacts behavior, and how it interacts with fentanyl in rodent models of opioid administration. Despite commentary from scientists, politicians, and public health officials, it is not known if xylazine impacts the efficacy of naloxone, the opioid receptor antagonist used to reverse opioid induced respiratory depression. Furthermore, few studies have examined the effects of xylazine alone, without co-administration of ketamine. Here, we examine the impact of xylazine alone and in combination with fentanyl on several key behaviors in male and female mice. We demonstrate differential locomotor responses by dose and sex to xylazine. Surprisingly, our results further indicate that naloxone precipitates withdrawal from xylazine and a fentanyl/xylazine combination, in both sexes, with enhanced sensitivity in females. Further, we show that xylazine is a full agonist at the kappa opioid receptor, a potential mechanism for its naloxone sensitivity. One-Sentence SummaryWe present surprising new insights into xylazine and fentanyl pharmacology with immediate implications for clinical practice and frontline public health.

neuroscience↗

bioRxiv2022

Multisensory integration of social signals by a pathway from the basal amygdala to the auditory cortex in maternal mice

Social encounters are inherently multimodal events, yet how and where social cues of distinct sensory modalities merge and interact in the brain is poorly understood. When their pups wander away from the nest, mother mice use a combination of vocal and olfactory signals emitted by the pups to locate and retrieve them. Previous work revealed the emergence of multisensory interactions in the auditory cortex (AC) of both dams and virgins who co-habitate with pups ( surrogates). Here we identify a neural pathway that integrates information about odors with responses to sound. We found that a scattered population of glutamatergic neurons in the basal amygdala (BA) projects to the AC and responds to odors, including the smell of pups. These neurons exhibit increased activity when the female is searching for pups that terminates upon contact. Finally, we show that selective optogenetic activation of BA-AC neurons modulates responses to pup calls, and that this modulation switches from predominantly suppressive to predominantly excitatory after maternal experience. This supports an underappreciated role for the amygdala in directly shaping sensory representations in an experience-dependent manner. We propose that the BA-AC pathway integrates olfaction and audition to facilitate maternal care, and speculate that it may carry valence information to the AC.

neuroscience↗

bioRxiv2020

Methods for Running a Successful Women-in-STEM Organization on an Academic Campus

The current academic culture facing women in science, technology, engineering, and math (STEM) fields in the United States has sparked the formation of grassroots advocacy groups to empower female scientists-in-training. However, the impact of these initiatives often goes unmeasured and underappreciated. Our Women in Science and Engineering (WiSE) organization serves post-doctoral researchers, graduate students, and research technicians (trainees) at a private research institute for biological sciences. Here we propose the following guidelines for cultivating a successful women-in-STEM-focused group based upon survey results from our own scientific community as well as the experience of our WiSE group leaders. We hope these recommendations can provide guidance to advocacy groups at other research and academic organizations that wish to strengthen their efforts. While our own group specifically focuses on the underrepresented state of women in science, we hope these guidelines may be adapted and applied to groups that advocate for any minority group within the greater scientific community (i.e. those of gender, race/ethnicity, socioeconomic background, sexual orientation, etc.).

scientific communication and education↗