published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

This study examined the effect of prolonged differential housing and/or diet following exposure to chronic restraint stress on body weight, body fat weight, body fat composition and corticosterone, glucose, insulin and leptin levels. To this end, male Wistar rats were individually-housed (IH) or pair-housed (PH) and fed a condensed milk diet (CD) or a mushy rat chow diet (MD) for twelve weeks. Subsequently, all rats underwent chronic restraint stress (CRS) for seven hours/day for four weeks. During CRS, only PH rats fed MD continued to gain weight, while growth of the other groups was stunted. Housing and diet impacted on body fat weights, where PH caused increased retrorenal fat (P<0.001) in rats fed MD, while in rats fed CD, PH gave rise to less visceral (P<0.01) and more interscapular (P<0.05) and retrorenal fat (P<0.001). The CD resulted in more retrorenal (P<0.001) and interscapular fat (P<0.05) in PH rats, with more visceral (P<0.001) and retrorenal fat (P<0.01) in IH rats. Housing influenced only the fatty acid profiles of the liver and subcutaneous fat in rats fed CD. The CD caused differing fatty acid profiles of the liver, subcutaneous fat, visceral fat, interscapular fat and muscle in PH rats, while altering the fatty acid profiles of the liver, subcutaneous fat, interscapular fat and muscle in IH rats. Housing and diet did not result in differences in corticosterone, insulin and glucose concentrations, while both resulted in significantly elevated leptin levels in PH rats fed CD. Therefore the types of housing and diet have various effects on body weight and glucose and fat metabolism following chronic stress. This dissertation is dedicated to My dear parents, Jeff and Avril Ackerman, for their on-going support My loving husband, Brandon, for his encouragement, assistance and patience My children, Elazar Tzvi, Sara Esther, Yaakov Yehuda and Rossi Bear who have been my stress alleviators and Idah Rangwato and Annah Sibanda who are my right-hand ladies and have made it possible to complete this dissertation- Thank you!

In rats anaesthetised with enflurane, Iexamined.the response of coccygeal primary afferents fibres to noxious thermal and mechanical stimulation and to innocuous brushing, during transient ischaemia and reperfusion of their receptive fields on the tail. Ischaemia was induced by occluding the blood supply to the tail for 30 min using a tourniquet. I discovered four different groups of afferent fibres, distinguished by conduction velocity and modality, A{3fibres responding to both brush and pinch of their receptive fields showed decreased sensitivity to brush during both ischaemia and reperfusion; Ao fibres responding to pinch were unaffected by either ischaemia or reperfusion, C fibres responding to noxious heat (49· C) and pinch showed hypersensitivity during reperfusion, especially immediately after release of the tourniquet. Another group of C fibres, presumably chemosensitive, became more actiVA during ischaemia and exhibited a 7-fold increase in firing rate during receptive field reperfuslon in the absence of obvious stimuli. These results indicate that during reperfuslon of the rat tail following transient ischaemia, myelinated fibres do not increase their input to the CNS, while C fibres became more active and showed sensitization to noxious stimulation of their receptive fields. The enhanced CNS nociceptive activity which occurs during reperfusion consequently results from both peripheral and. central sensitization. / GR2017

A rat model of novelty-seeking phenotype predicts vulnerability to nicotine relapse where locomotor reactivity to novelty is used to rank high (HR) versus low (LR) responders. This dissertation examines the neuropeptidergic and structural substrates of the expression of locomotor sensitization to a low dose nicotine challenge and associated social anxiety-like behavior following chronic intermittent nicotine exposure during adolescence in the LRHR phenotype. Data show the long-lasting nature of behavioral sensitization to nicotine and abstinence-related social anxiety-like behavior in nicotine pre-trained HRs compared to saline pre-trained controls. Moreover, this behavior is accompanied by an imbalance between the brain antistress/antianxiety, i.e., neuropeptide Y (NPY), and stress, i.e., corticotrophin releasing factor (CRF) systems in the amygdala. Moreover, a deficit in NPY signaling marked with decreased NPY and increased NPY Y2 receptor (Y2R) mRNA levels is observed in the hip pocampus, along with mossy fiber reorganization in nicotine pre-trained HRs. Furthermore, a Y2R antagonist administered 1 wk of abstinence reverses these behavioral, molecular and morphological effects in nicotine-exposed HRs. Additionally, the role of amygdalar synaptic plasticity in longlasting social withdrawal is also investigated by assessing brain-derived neurotrophic factor (BDNF) and spinophilin mRNA levels in HRs following a behaviorally-sensitizing nicotine regimen. A persistent increase in BDNF and spinophilin mRNA levels in the basolateral amygdala (BLA) is observed in nicotine pre-trained HRs even across a long (3-wk) abstinence spanning into young adulthood. This strongly suggests BDNFmediated long-lasting neuroplasticity within the BLA that may regulate abstinence-related negative affect in HRs. / Moreover, a cannabinoid receptor 1 (CB1R) antagonist, AM251 treatment during a short (1-wk) abstinence is ineffective in reversing social anxiety, nicotine-induced neuroplasticity and the neuropeptidergic changes in the amygdala, although it is effective in reversing the expression of locomotor sensitization to challenge nicotine even following a long (3-wks) abstinence. Furthermore, the identical AM251 treatment given during the late phase of a long (3-wk) abstinence further augments social withdrawal and associated BLA plasticity in nicotine pre-trained HRs. These findings implicate neuropeptidergic and neuroplastic changes in the hippocampus and the amygdala in vulnerability to the long-lasting behavioral effects of nicotine in the novelty-seeking phenotype. / by Cigdem Aydin. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Thesis (Ph.D.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

Thesis (M.A.)--State University of New York at Binghamton, Psychology Department, 2006. / Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Psychology Department, 2006. / Includes bibliographical references.

Thesis (Ph.D.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 164-173). Also available online.

Thesis (M.S.)--University of Massachusetts Amherst, 2009. / Includes bibliographical references (p. 47-59).