Date of Award

7-2019

Document Type

Thesis

Degree Name

Master of Arts in Psychological Science

Department

Psychology

First Reader/Committee Chair

McDougall Sanders

Abstract

The neurochemical changes occurring between the preweanling period and adolescence could be crucial for understanding the role development plays in the manifestation of psychotic behaviors. N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) fully attenuates the DA agonist-induced behaviors of adult rats, while potentiating the DA agonist-induced locomotor activity of preweanling rats. My specific hypotheses were as follows: (1) Systemically administered EEDQ would block the cocaine-induced locomotor activity of adult rats. (2) Systemically administered EEDQ would potentiate the cocaine-induced locomotion of preweanling rats. (3) EEDQ would increase the Emax values (a measure of D2 receptor sensitivity) of preweanling rats, but not adolescent or adult rats. And, (4) EEDQ would reduce dorsal striatal β-arrestin-2 (ARRB2) and GRK6 levels (measures of D2 receptor sensitivity) of preweanling rats. Behavioral results were as expected, because EEDQ attenuated the locomotion of adult and adolescent rats, while EEDQ potentiated locomotor activity of preweanling rats. EEDQ enhanced the GTPγS binding of preweanling rats, while depressing ARRB2 levels. These results are consistent with the overarching hypothesis that EEDQ causes DA supersensitivity in preweanling rats. Thus, it is here proposed that EEDQ inactivates a significant number of D2 receptors in preweanling rats, but that the remaining D2 receptors are supersensitive and capable of mediating a potentiated locomotor response.

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