Research

Temperature Dependant Modulation of Synaptic Transmission: The Role of Adenosine A1 and A2a Receptors

Adenosine is present throughout the human body, both as part of cellular energy cycles and as a signaling molecule. It plays an important role in regulating the excitability of the brain and is known to be as a sleep-promoter, pain-reliever, and seizure reducer. Because of these properties, understanding the regulation and actions of adenosine may hold important clinical implications.

Adenosine exerts its influence on the central nervous system through several receptor subtypes. We will be looking directly into the relationship between two of these subtypes, the adenosine A1 and adenosine A2a receptors, which have opposing effects on neuronal excitability (inhibitory and excitatory, respectively). Preliminary trials have shown that adenosine is regulated by temperature. The aim of this study is to further understand the relationship between temperature of adenosine and the regulation of adenosine receptor activity in the nervous system. Using extracellular electrophysiological recordings from hippocampal slices (Schaffer Collateral pathway) from 4-5 week old Sprague-Dawley rats we looked further into this phenomenon taking recordings at the specific temperatures of 25ºC, 33ºC, and 37ºC and applying adenosine receptor antagonists. These results show that the effect of the adenosine A1 receptor is dominant at 33ºC, whereas the A2a receptor subtype is activated at other temperatures above and below 33ºC. Understanding the relationship between adenosine and its receptors, both in vivo and in hippocampal slice preparations, may help design further strategies to regulate brain excitability through these specific receptor subtypes.

A Novel Sensory Discrimination Task Using Rodent Whiskers

The whisker system is the most well developed sensory system in the rodent, offering an unparalleled model for studying sensory discrimination. Rats were trained to use their whiskers in a novel Y-maze task, pairing a behavioral choice with whisker discrimination of smooth versus rough textures. Rats were placed in the start alley of the Y-maze, whereby they whisked two discriminanda on the left and right walls. The wall marked by the rough texture corresponded to the choice-alley containing a water reward. As animals learned to discriminate between textures, and associate the rougher texture with the reward, the task became increasingly difficult by minimizing the textural difference between the rough and smooth discriminanda. The goal of this study is to develop a novel task for studying the limits of sensory discrimination using the rat whisker system.