THE IMPACT OF INFLAMMATION ON THE REGULATION OF INTRACELLULAR CALCIUM IN CUTANEOUS NOCICEPTIVE NEURONS

The most effective way to treat clinical pain is to target the subpopulation of primary afferent neurons responsible. However, clinical pain is heterogeneous, reflecting, in part, differences in the relative contribution of different subpopulations of afferents. The functional heterogeneity of primary afferents is reflected in the heterogeneous regulation of intracellular Ca2+ ([Ca2+]i). Because the regulation of [Ca2+]i contributes to neuronal function, injury-induced changes in neuronal function may be due to dysregulation in the regulation of [Ca2+]i. Thus, the persistent inflammation-induced increase in the magnitude and duration of depolarization-evoked Ca2+ transient in a subset of putative nociceptive cutaneous DRG neurons served as the focus of this thesis. I first ruled out the contribution of Ca2+-induced Ca2+ release to the inflammation-induced increase in the evoked Ca2+ transient. Results of these experiments also indicated the presence of tightly segregated Ca2+ regulatory domains where Ca2+ transients evoked via Ca2+ influx and release from intracellular stores are functionally isolated. Parametric analysis demonstrated that inflammation-induced changes in evoked Ca2+ had a high threshold for activation, thus I focused on low affinity Ca2+ extrusion mechanism, Na+/Ca2+ exchanger (NCX). I demonstrated that NCX regulates the decay of the evoked transient in the same subset of putative nociceptive afferents modified by inflammation, and can influence axonal [Ca2+]i levels, resting membrane potential, and nociceptive threshold. Finally, I confirmed a role for NCX in response to persistent inflammation, such that the increase in the duration of the evoked transient is due to a loss of NCX in the cell body due to an increase in unidirectional NCX3 trafficking to the peripheral terminals. These observations serve as the basis for my current working hypothesis that the inflammation-induced changes in trafficking of NCX3, underlie three major aspects of the inflammatory response: an increase in transmitter release from the central terminal to contribute to inflammatory hyperalgesia, a change in gene expression secondary to altered Ca2+ transients in the cell body, and a decrease in the neurogenic inflammatory response in the periphery secondary to a decrease in transmitter release. Increasing NCX function may be a potentially novel therapeutic strategy for treatment of inflammatory pain

Carbon Nanotube Membranes for Use in the Transdermal Treatment of Nicotine Addiction and Opioid Withdrawal Symptoms

Transdermal systems are attractive methods of drug administration specifically when treating patients for drug addiction. Current systems however are deficient in therapies that allow variable flux values of drug, such as nicotine for smoking cessation or complex dosing regimens using clonidine when treating opioid withdrawal symptoms. Through the use of functionalized carbon nanotube (CNT) membranes, drug delivery to the skin can be controlled by applying a small electrical bias to create a programmable drug delivery system. Clearly, a transdermal patch system that can be tailored to an individual\u27s needs will increase patient compliance as well as provide much more efficient therapy. The purpose of this paper is to discuss the applicability of using carbon nanotube membranes in transdermal systems for treatment of drug abuse

Transdermal Capabilities of Clonidine for Opiate Withdrawal

Opiate is used to describe drugs derived from opium such as morphine, heroin, and codeine. The discontinuation of opiates from the human body can cause an excess in excited locus coeruleus neurons (located in the brainstem), the reason for physical symptoms of withdrawal. Clonidine, a direct acting alpha-2 noradrenergic agonist, is able to lessen withdrawal distress for addicts and therefore improve the withdrawal process. The opiate withdrawal dosing regimen is complex in which it requires multiple oral doses multiple times a day and then gradually tapering over at least a five day period. Transdermal delivery over oral dosing is preferred because it is easier to follow with such a complex schedule. This drug could be delivered transdermally varying the amounts of drug released into the blood thus eliminating the withdrawal symptoms of an opiate addict. In order to use clonidine via a transdermal delivery route, the therapeutic feasibility needed to be determined. Desired flux rates were reached and profiles of concentrations are linear. Therefore, clonidine can be tested in a patch system involving a carbon nanotube membrane. This membrane system, in the future, will include an electrical bias to allow the transdermal delivery system to be programmable, dispensing clonidine in set concentrations as required in the dosing regimen

Protein levels of heat shock proteins 27, 32, 60, 70, 90 and thioredoxin-1 in amnestic mild cognitive impairment: An investigation on the role of cellular stress response in the progression of Alzheimer disease

Heat shock proteins (HSPs) are highly regulated proteins that are involved in normal cellular activity and are up-regulated when the cell is exposed to stress such as heat or excess reactive oxygen species (ROS) production. HSPs are molecular chaperones that mediate the proper folding of proteins and promote recovery of the native conformations of proteins lost due to stress. Improperly folded or denatured proteins tend to aggregate and accumulate in cells. A number of neurodegenerative diseases such as Parkinson disease (PD) and Alzheimer disease (AD) have been called "protein misfolding disorders" due their characteristic pathology. Until now the exact mechanism(s) of AD progression and pathogenesis largely remains unknown. Reasoning that stress is present in brain in AD, we tested the suggestion that HSP levels would be increased in amnestic mild cognitive impairment (aMCI), a transition stage between normal aging and AD. Accordingly, in the present study we measured the levels of HSPs in hippocampus, inferior parietal lobule (IPL) and cerebellum of subjects with aMCI. The results show a general induction of HSPs and decreased levels of Thioredoxin 1 in aMCI brain suggesting that alteration in the chaperone protein systems might contribute to the pathogenesis and progression of AD. The results also are consistent with the notion that targeting HSP could be a therapeutic approach to delay the progression of aMCI to AD. (C) 2010 Elsevier B.V. All rights reserved