Denning, A. | bioRxiv Science

bioRxiv2026

Glucose and fructose differently mediate alcohol cocktail drinking in female and male rats: interaction of glucose and alcohol on post-ingestive behavior

Sweetened alcoholic beverages are thought to contribute to developing Alcohol Use Disorder by increasing palatability. One monosaccharide, glucose, readily enters the brain more than fructose and directly impacts the activity of central neurons. The objective of this study is to determine the impact of glucose versus fructose on alcohol drinking patterns in female and male rats. Rats drank alcohol cocktails (1.25%-10%) containing either glucose or fructose (10%) in 4-hour sessions. We sought to parse orosensory effects from post-ingestive central effects by analyzing drinking microstructure. We compared measures of palatability and post-ingestive feedback between early and later in the session when brain levels of alcohol and glucose are different. We found that rats of both sexes drank more low alcohol glucose cocktails than cocktails containing fructose by volume and by overall calories. When considering the dose of alcohol, glucose potentiated alcohol intake by shifting the dose-response curve leftward compared to similar fructose cocktails. We found that drinking patterns associated with palatability remained stable for both types of cocktails over the entire drinking session. In contrast, post-ingestive behavior related to brain mediated satiety or positive feedback showed a greater influence of the session time, as well as a greater interaction with sex. Overall, our results suggest that glucose and alcohol interact to impact central regulation of cocktail drinking. This highlights that the type of sugar within cocktails interacts and ultimately have different effects on brain regulated alcohol drinking.

pharmacology and toxicology↗

bioRxiv2023

Comparison of histological delineations of medial temporal lobe cortices by four independent neuroanatomy laboratories

The medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimers disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical schools rely on different cytoarchitectonic definitions of these subregions, it is unclear to what extent their delineations of MTL cortex subregions overlap. Here, we provide an overview of cytoarchitectonic definitions of the cortices that make up the parahippocampal gyrus (entorhinal and parahippocampal cortices) and the adjacent Brodmann areas (BA) 35 and 36, as provided by four neuroanatomists from different laboratories, aiming to identify the rationale for overlapping and diverging delineations. Nissl-stained series were acquired from the temporal lobes of three human specimens (two right and one left hemisphere). Slices (50 {micro}m thick) were prepared perpendicular to the long axis of the hippocampus spanning the entire longitudinal extent of the MTL cortex. Four neuroanatomists annotated MTL cortex subregions on digitized (20X resolution) slices with 5 mm spacing. Parcellations, terminology, and border placement were compared among neuroanatomists. Cytoarchitectonic features of each subregion are described in detail. Qualitative analysis of the annotations showed higher agreement in the definitions of the entorhinal cortex and BA35, while definitions of BA36 and the parahippocampal cortex exhibited less overlap among neuroanatomists. The degree of overlap of cytoarchitectonic definitions was partially reflected in the neuroanatomists agreement on the respective delineations. Lower agreement in annotations was observed in transitional zones between structures where seminal cytoarchitectonic features are expressed more gradually. The results highlight that definitions and parcellations of the MTL cortex differ among neuroanatomical schools and thereby increase understanding of why these differences may arise. This work sets a crucial foundation to further advance anatomically-informed human neuroimaging research on the MTL cortex.

neuroscience↗