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The Barson Lab Research

Why do certain individuals overconsume substances that can be harmful to them?

Our laboratory employs a multidisciplinary approach to determine the neural basis of excessive ingestive behavior and why this varies across individuals.

Specifically, we are interested in how neuropeptides in the limbic system can act and interact to lead to alcoholism and obesity and how these actions may differ across individuals with the same disorder.

Paraventricular Thalamus

Alcohol drinking causes orexin from the hypothalamus to stimulate neurons in the anterior PVT.

Alcohol drinking causes orexin from the hypothalamus to stimulate neurons in the anterior PVT.

 
The paraventricular nucleus of the thalamus (PVT) functions as a major node in the limbic system, connecting homeostatic forces of the hypothalamus that act to maintain energy levels with non-homeostatic forces of other limbic nuclei that promote reward-seeking.

Our laboratory is currently investigating how subregions of the PVT communicate with other limbic brain regions to play distinct roles in alcohol and sucrose intake.

Neuropeptides

The neuropeptide orexin (OX), released from the hypothalamus, specifically stimulates substance P in the thalamus.

The neuropeptide orexin (OX), released from the hypothalamus, specifically stimulates substance P in the thalamus.

 
Neuropeptides are a class of neurochemicals that operate over a long time scale and are often transcribed in highly localized brain regions. This allows neurotransmitters to affect very specific behaviors.

In studying ingestive behavior, our laboratory focuses on how it is influenced specifically by neuropeptides and how neuropeptides interact with each other.

Alcoholism

Low levels of substance P (SP) promote binge drinking of alcohol when microinjected into the anterior paraventricular thalamus.

Low levels of substance P (SP) promote binge drinking of alcohol when microinjected into the anterior paraventricular thalamus.

 
Current projects on alcoholism focus on how neuropeptides in subregions of the paraventricular thalamus as well as in the hypothalamus can promote binge drinking.

Food Intake

Rats will escalate their intake of a sucrose solution when it is offered on a restricted access schedule.

Rats will escalate their intake of a sucrose solution when it is offered on a restricted access schedule.

 
Currently, the laboratory is examining how drinking sucrose solutions can be affected by neuropeptides in subregions of the paraventricular thalamus and the hypothalamus. By comparing these findings with those for alcohol drinking, we will be able to determine if ingestive behavior systems are universal or of they are specific for the substance being consumed.

Heterogeneity

Individuals who drink excess alcohol due to their poor metabolism show different neuropeptide disturbances than those who drink due to their preference for novelty.

Individuals who drink excess alcohol due to their poor metabolism show different neuropeptide disturbances than those who drink due to their preference for novelty.

 
Alcoholism and overeating are heterogenous disorders in that individuals engage in these behaviors for a variety of reasons, both behavioral and neurochemical.

We are currently involved in a series of studies investigating not just how neuropeptides can lead individuals to binge on alcohol or overeat, but how they may do this differently in different individuals.

Techniques

 
The laboratory utilizes a wide variety of techniques to investigate the role of neuropeptides in reinforcing substance intake. These include:

  • Quantitative real-time PCR
  • ELISA, immunohistochemistry, in situ hybridization
  • Operant and non-operant (voluntary) substance self-administration
  • Activity chamber locomotor behavior, hole board exploration, place preference, elevated plus maze anxiety and light-dark box anxiety
  • Microinjection, tract tracing and chemogenetics

 
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Neuropeptide disturbances images from the Barson Lab at Drexel University College of Medicine.