Women are more susceptible to several aspects of drug addiction than men, including relapse following stressful events. Addictive processes critically involve hippocampal circuitry that supports spatial and episodic memory acquisition processes. In contrast to the impaired cognition observed in males after chronic stress, females display enhanced spatial memory following chronic stress suggesting ovarian hormone involvement. Within the dorsal hippocampus, it is well established that ovarian steroids, in particular estrogens, can modulate CA1 pyramidal cell activity and long-term potentiation (LTP), the cellular model of learning. During the last grant period we found that ovarian hormones also regulate enkephalins and the mu- and delta-opioid receptors (MORs and DORs, respectively) in a manner that could promote learning processes under certain conditions. Specifically, at proestrus (high estrogen): 1) enkephalin levels are elevated in mossy fibers (MFs), which synapse on the dendrites of CA3 pyramidal cells;2) increased MORs are present on the plasma membrane of parvalbumin GABAergic interneurons, which inhibit CA3 pyramidal cells;3) fewer DORs are present on the plasma membrane of pyramidal cells;and 4) MF stimulation may induce an opioid-dependent potentiation of CA3 field excitatory post- synaptic potentials. Chronic stress, which can trigger the release of opioid peptides, has maladaptive morphological responses in males that are not seen in females, and may also elevate MOR expression in parvalbumin interneurons in females. This renewal application proposes to test the central hypothesis that chronic stress leads to adaptive changes in the opioid system of females to promote CA3 LTP and other plastic processes that support drug-related learning. Approaches using a combination of light and electron microscopic immunocytochemistry, RT-PCR, in situ hybridization, in vitro slice electrophysiology and immobilization stress will test this hypothesis.
Aim 1 will determine if chronic stress alters: 1) the levels and/or subcellular distribution of enkephalins within MFs and in lateral perforant path (LPP) afferents to CA3 and 2) opioid-mediated LTP and/or other forms of opioid-mediated plasticity at MF/LPP- CA3 synapses in a manner promoting learning processes in females.
Aim 2 will determine if following chronic stress MORs and DORs have altered: 1) expression and cellular distributions;2) trafficking within select cell types;and/or 3) phosphorylated levels or distributions in the CA3 region in a manner promoting excitation and learning processes in females.
The results of these studies will elucidate potential mechanisms through which ovarian steroids, by targeting neurons that release, express or respond to opioids, may influence hippocampal-dependent learning relevant to drug abuse. These studies will improve our understanding of sex differences in the nature and etiology of drug abuse and have implications for tailoring treatment interventions to maximize positive outcomes for females and males.
|Mende, Michael; Fletcher, Emily V; Belluardo, Josephine L et al. (2016) Sensory-Derived Glutamate Regulates Presynaptic Inhibitory Terminals in Mouse Spinal Cord. Neuron 90:1189-202|
|Almey, Anne; Milner, Teresa A; Brake, Wayne G (2016) Estrogen receptor Î± and G-protein coupled estrogen receptor 1 are localized to GABAergic neurons in the dorsal striatum. Neurosci Lett 622:118-23|
|Van Kempen, Tracey A; Narayan, Ankita; Waters, Elizabeth M et al. (2016) Alterations in the subcellular distribution of NADPH oxidase p47(phox) in hypothalamic paraventricular neurons following slow-pressor angiotensin II hypertension in female mice with accelerated ovarian failure. J Comp Neurol 524:2251-65|
|Chung, Sun Young; Kishinevsky, Sarah; Mazzulli, Joseph R et al. (2016) Parkin and PINK1 Patient iPSC-Derived Midbrain Dopamine Neurons Exhibit Mitochondrial Dysfunction and Î±-Synuclein Accumulation. Stem Cell Reports 7:664-677|
|Mazid, Sanoara; Hall, Baila S; Odell, Shannon C et al. (2016) Sex differences in subcellular distribution of delta opioid receptors in the rat hippocampus in response to acute and chronic stress. Neurobiol Stress 5:37-53|
|Rogers, Sophie A; Kempen, Tracey A Van; Pickel, Virginia M et al. (2016) Enkephalin levels and the number of neuropeptide Y-containing interneurons in the hippocampus are decreased in female cannabinoid-receptor 1 knock-out mice. Neurosci Lett 620:97-103|
|Marques-Lopes, Jose; Lynch, Mary-Katherine; Van Kempen, Tracey A et al. (2015) Female protection from slow-pressor effects of angiotensin II involves prevention of ROS production independent of NMDA receptor trafficking in hypothalamic neurons expressing angiotensin 1A receptors. Synapse 69:148-65|
|Harte-Hargrove, Lauren C; Varga-Wesson, Ada; Duffy, Aine M et al. (2015) Opioid receptor-dependent sex differences in synaptic plasticity in the hippocampal mossy fiber pathway of the adult rat. J Neurosci 35:1723-38|
|Ma, Qian; Yang, Jianmin; Li, Thomas et al. (2015) Selective reduction of striatal mature BDNF without induction of proBDNF in the zQ175 mouse model of Huntington's disease. Neurobiol Dis 82:466-77|
|Waters, Elizabeth M; Thompson, Louisa I; Patel, Parth et al. (2015) G-protein-coupled estrogen receptor 1 is anatomically positioned to modulate synaptic plasticity in the mouse hippocampus. J Neurosci 35:2384-97|
Showing the most recent 10 out of 116 publications