Lipid Raft Dynamics in the Adolescent Brain under the Influence of Chronic Ethanol and Caffeine
Authors: Rhoads Dennis E. , O'Shea Calliope , Telatin Marta 
Published: June 2021

Simultaneous consumption of alcohol with stimulants such as caffeine and amphetamine has become increasingly prevalent, particularly among adolescents already prone to binge drinking. Initial work in this lab has modeled prolonged alcohol‐stimulant co‐use in behavioral studies of adolescent Long‐Evans rats. This work suggested that stimulants mask or block symptoms associated with alcohol withdrawal. Thus, stimulants may lessen the awareness of growing dependence on alcohol when consumed regularly with alcohol. The goal of the present study was to determine whether lipid raft dynamics play a role in the cellular mechanisms by which caffeine and ethanol interact in this model. Lipid rafts were isolated as detergent resistant membrane fragments from forebrain regions of adolescent rats fed liquid diets with alcohol alone or in combination with caffeine. Pair‐fed rats with no additions to the diet or with caffeine alone were used as controls. All procedures involving rats were reviewed and approved by the Institutional Animal Care and Use Committee for compliance with regulations and best practices. Western blotting was used to analyze fractions for the raft marker flotilin and the NMDA‐subtype of glutamate receptor. Two fractions were found to contain flotilin with a relatively small percentage (<20%) of the marker found in the less buoyant of the two fractions. However, there was a highly significant 2–3 fold increase in this less buoyant fraction from membranes derived from the ethanol‐fed rats. This increase did not occur when rats were consuming caffeine along with alcohol under conditions that result in decreased alcohol withdrawal severity. Looking at NMDA receptor expression, we first confirmed that there was an upregulation of NMDA receptors during chronic alcohol consumption. NMDA receptors were expressed in both raft fractions in all treatment groups. However, paralleling the increase in flotilin, NMDA receptor expression was significantly higher in the less buoyant fraction following chronic ethanol consumption. This elevated expression of NMDA receptor was not observed when the rats consumed caffeine and ethanol. Neither flotilin nor NMDA receptor expression differed by treatment group in the more prominent higher buoyancy raft fraction. Location of NMDA receptors in what appears to be an “alcohol responsive” raft fraction may help account for its upregulation during chronic alcohol consumption. Moreover, the shift does not occur with caffeine “co‐use” suggesting lipid raft dynamics may be a site associated with the ability of caffeine to antagonize adaptive responses of the brain to chronic ethanol. Given that the appearance of withdrawal symptoms can be a cue to emerging dependency, understanding the ability of stimulants to mask or block these symptoms is crucial to both education and treatment strategies related to adolescent alcohol abuse.

Support or Funding Information

Supported by a Grant‐in‐Aid from Monmouth University and by the Department of Biology.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.