<p> Compensatory synaptic vesicle endocytosis during kiss-and-run vesicle fusion is not fully understood. Specifically, it is unclear whether proteins involved in classical clathrin-mediated endocytosis (CME) are also required for vesicle retrieval following kiss-and-run vesicle fusion. Part of the impetus for the work presented in this thesis was to determine whether one such protein, dynamin, is responsible for vesicle retrieval during kiss-and-run fusion. Dynamin is a key protein in membrane fission during CME, providing an energy utilizing GTPase reaction to sever the vesicle from the plasma membrane. However, because vesicles may not fully collapse during kiss-and-run fusion it is unclear whether there exists an analogous role for dynamin in this process. Utilizing a 5-HTmediated model of presynaptic inhibition favoring kiss-and-run vesicle fusion in a model synapse, the lamprey giant reticulospinal synapse, I present findings that demonstrate kiss-and-run fusion as a frequency-dependent, calcium-sensitive effect of 5-HT. Furthermore, I demonstrate that dynamin does not appear to be conclusively involved in compensatory endocytosis during kiss-and-run vesicle fusion. While addressing this question, I employed different means of pharmacologically inhibiting dynamin. These experiments revealed that inhibition of the action of dynamin, either by inactivating its GTPase activity, or by modifying its interaction with amphiphysin, depletes synaptic vesicle numbers at presynaptic active zones. This finding suggests that dynamin is important in maintaining vesicle pools in resting presynaptic terminals, but also provides new avenues for better elucidating potential roles of endocytic proteins in paradigms used to investigate kiss-and-run vesicle fusion.</p>

<p> Sexual receptivity in the female rat is dependent on dose and duration of estradiol exposure. A 2&micro;g dose of estradiol benzoate (EB) primes reproductive behavior circuits but without subsequent progesterone does not facilitate lordosis. However, 50&micro;g EB facilitates lordosis after 48 hours. Both EB doses activate membrane estrogen receptor-&alpha; complexed with metabotropic glutamate receptor-1a (mER&alpha;-mGluR1a), activating a multisynaptic circuit in the arcuate nucleus (ARH). I hypothesized that 50&micro;g EB downregulates ER&alpha; and mER&alpha;-mGluR1a complexes in the ARH. Total ARH ER&alpha; protein was reduced 48 hours after 50&micro;g EB, but the 2&micro;g dose was intermediate between oil and 50&micro;g EB. mER&alpha; that co-immunoprecipitated with mGluR1a were greater 48 hours after 2&micro;g EB treatment versus rats receiving 50&micro;g EB. Progesterone signals rapidly but not through progesterone receptor-dopamine D1 receptor complexes. These results indicate 2&micro;g EB maintains but 50&micro;g EB downregulates mER&alpha;-mGluR1a to regulate lordosis.</p>

<p> HIV associated neurocognitive disorders (HAND) encompass a spectrum of cognitive deficits that affect 40-70% of HIV-infected individuals, despite antiretroviral therapy. Monocytes are among the first cells infected by HIV and are critical mediators of HAND as they facilitate viral seeding of the central nervous system (CNS) upon their transmigration across the blood brain barrier (BBB). Monocyte subpopulations exist with differing levels of maturation and functions. Monocytes that express CD14, the LPS receptor, and CD16, the Fcylll receptor, are a mature population of cells that are highly susceptible to HIV. While CD14⁺CD16⁺ monazites are believed to mediate the neuropathogenesis of HIV, little is known about the mechanisms that contribute to their diapedesis across the BBB. As the CD14⁺CD16⁺ monocyte represents a small percentage of monocytes in healthy individuals, we developed a tissue culture model to enrich for this population. We found that there was a selective transmigration of CD14⁺CD16⁺ monocytes across our BBB model, with little migration of other monocyte populations. HIV infection resulted in the increased transmigration of CD14⁺CD16⁺ monocytes in response to CCL2 relative to uninfected cells, which was due to increased CCR2 and a heightened sensitivity to the chemokine. The junctional proteins JAM-A and ALCAM were also critical for this transmigration as antibody blockade reduced the number of migrating monocytes. These CD14+CD16+ monocytes were present in significantly greater numbers in HIV-infected people, despite viral suppression, in contrast to individuals without HIV. CCR2 was increased on CD14⁺CD16⁺ monocytes in HIV-infected individuals with HAND compared to those with normal cognition and was predictive of fluctuations in cognitive impairment upon longitudinal study. ALCAM and JAM-A were increased on CD14⁺CD16⁺ monocytes in those with HIV compared to HIV seronegative people. Blocking antibodies to ALCAM and JAM-A inhibited the transmigration of CD14⁺CD16⁺ monocytes, but not of T cells, suggesting their importance in specifically facilitating monocyte transmigration across the BBB. Our findings indicate therapeutic strategies to monitor HAND, and that may decrease the entry of CD14⁺CD16⁺ monocytes into the CNS of HIV-infected individuals, contributing to the eradication of neuroinflammation, HAND, and CNS viral reservoirs.</p>

Thesis (Ph.D.)--University of California, San Francisco, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4213. Adviser: Matthias Hebrok.

Thesis (Ph.D.)--University of California, San Francisco, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7143. Adviser: Lily Y. Jan.

Thesis (Ph.D.)--University of California, San Francisco, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7058. Adviser: David Julius.

Thesis (Ph.D.)--University of California, San Francisco, 2008. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7137. Adviser: Bruce Conklin.

Thesis (Ph.D.)--University of California, San Francisco, 2008. / Source: Dissertation Abstracts International, Volume: 69-06, Section: B, page: 3358. Adviser: Arturo Alvarez-Buylla. Includes supplementary digital materials.

Thesis (Ph.D.)--University of California, San Francisco, 2007. / Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 0796. Adviser: Graeme Davis.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4303. Adviser: Ellen Evans. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.