Thesis (Ph. D.)--UCLA, 2009. / Vita. Description based on print version record. Includes bibliographical references (leaves 179-202).

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on July 13, 2010). Thesis advisor: Amy DeClue. "May 2010" Includes bibliographical references.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

No description available.

No description available.

No description available.

Graduation date: 1995

Spinal cord neurons can support a simple form of instrumental learning that can be used to assess behavioral potential (plasticity) within this system. In this paradigm, subjects completely transected at the second thoracic vertebra learn to minimize shock exposure by maintaining a hindlimb in a flexed position. Preexposure to uncontrollable shock (shock independent of leg position) disrupts this learning. Activation of opioid receptors seems to contribute to the expression of the behavioral deficit observed after uncontrollable shock. Intrathecal application of naltrexone, a nonselective opioid receptor antagonist, blocked the expression, but not the induction, of the deficit. Treatment with nor-BNI, a kappa receptor antagonist, prior to testing had a similar effect, whereas mu (CTOP) and delta (naltrindole) receptor antagonists did not block the deficit. These findings suggest that prior exposure to uncontrollable shock induces a kappa opioid mediated event that inhibits learning. The current study examined the role of the kappa receptor in the behavioral deficit. Only GR89696, a selective kappa-2 receptor agonist, inhibited learning. This impairment was dose-dependent and, at the highest dose (30 nmol), inhibited learning for 96 hours. However, GR89696 and uncontrollable shock did not interact in an additive fashion. Instead, an intermediate dose attenuated the induction of the deficit. These findings suggest that activation of kappa receptors, specifically the kappa-2 subtype, inhibit instrumental learning and block the induction of the learning deficit. Both effects may be linked to the inhibition of NMDA-mediated plasticity.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 72-80).

Prescription drug abuse, in particular prescription opioid abuse is a public health concern. One measurement of the effects of prescription opioids is the number of patients visiting the emergency departments (ED) with opioid-related problems. Knowing more about the patients who visit the ED with opioid-related problems may assist in addressing this problem. This study examined hospital and prescription claims of Texas Medicaid enrollees from 2008 to 2011 to determine whether demographic factors could help predict the opioid prescription history of the ED patients. Age, sex and race/ethnicity were used as demographic predictors. A patient’s prescriptive history was categorized as a non-prescribed user, a short-term user, or a long-term user based on Texas Medicaid prescription claims. Of the 1001 Texas Medicaid enrollees in our dataset who had a claim for an opioid-related ED visit, 622 were classified as non-prescribed users, 65 were short-term users, and 314 were long-term users. Our ordinal logistic regression model was a poor model for predicting prescriptive history. This study does suggest that the number of opioid-related ED visits in the Texas Medicaid population is increasing. The majority of Texas Medicaid enrollees in our study were classified as non-prescribed users. Focused efforts to address the growing problem of opioid-related ED visits cannot be limited to the patients being with claims for opioid prescriptions. / text