Master of Arts (MA)
Stress is known to exert an influence on neuroendocrine, autonomic, hormonal, and immune functioning. As a result of the debilitating effects of stress on numerous bodily systems, there exists a large body of research devoted to the etiology, physiological sequelae, and treatment of the condition. Further, the neurotransmitter serotonin (5-HT) has been implicated in stress responding. Presently, there is conflict in the literature as to the precise role serotonin plays in mediating the stress response. This study was an attempt to further elucidate the role of 5-HT in mediating an organism’s response to tail pinch stress and the open field. Previously, we have demonstrated that peripheral administration of the broad-spectrum 5-HT2 agonist, DOI, reduces stress responding in rats subjected to a tail pinch stressor (Hawkins, et al., 2002). This effect was fully blocked by peripheral coadministration of the broad spectrum 5-HT2 antagonist, ketanserin. The present study examined further the role of the 5-HT2 receptor subclass in mediating the stress response. We employed antagonists that selectively target either the 5-HT2A or 5-HT2C receptor in an effort to clarify the relative importance of each of these receptors in mediating the stress response. These compounds were injected subcutaneously in an effort to black the effects previously seen with DOI. DOI attenuated rearing and oral behavior directed at food, while increasing the frequency of head and body shakes in the open field. DOI-induced head shakes were blacked by the 5-HT2C antagonist, SDZ SER 082, as well as by a combination of SDZ SER 082 and the 5-HT2A antagonist, spiperone. Implications for the 5-HT2 receptor subclass in mediating stress responding are discussed.
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Hearn, John K., "Effects of 5-HT2 receptor ligands on tail pinch-induced stress responding and open field behavior" (2005). LSU Master's Theses. 143.