Pharmacy and Pharmaceutical Sciences Commons^™

Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage-dependent potassium (Kv) channels provide the repolarizing power that shapes the action potential duration and helps control the firing frequency of neurons. The K(+) permeation through the channel pore is controlled by an intracellularly located bundle-crossing (BC) gate that communicates with the voltage-sensing domains (VSDs). During prolonged membrane depolarizations, most Kv channels display C-type inactivation that halts K(+) conduction through constriction of the K(+) selectivity filter. Besides triggering C-type inactivation, we show that in Shaker and Kv1.2 channels (expressed in Xenopus laevis oocytes), prolonged membrane depolarizations also slow down the kinetics of VSD deactivation and BC gate closure during the …

Modeling Of Pharmacokinetics Of Cocaine In Human Reveals The Feasibility For Development Of Enzyme Therapies For Drugs Of Abuse, Fang Zheng, Chang-Guo Zhan

Pharmaceutical Sciences Faculty Publications

A promising strategy for drug abuse treatment is to accelerate the drug metabolism by administration of a drug-metabolizing enzyme. The question is how effectively an enzyme can actually prevent the drug from entering brain and producing physiological effects. In the present study, we have developed a pharmacokinetic model through a combined use of in vitro kinetic parameters and positron emission tomography data in human to examine the effects of a cocaine-metabolizing enzyme in plasma on the time course of cocaine in plasma and brain of human. Without an exogenous enzyme, cocaine half-lives in both brain and plasma are almost linearly …

Localization And Functional Characterization Of The Rat Oatp4c1 Transporter In An In Vitro Cell System And Rat Tissues, Kuei-Ling Kuo, Haining Zhu, Patrick J. Mcnamara, Markos Leggas

Pharmaceutical Sciences Faculty Publications

The organic anion transporting polypeptide 4c1 (Oatp4c1) was previously identified as a novel uptake transporter predominantly expressed at the basolateral membrane in the rat kidney proximal tubules. Its functional role was suggested to be a vectorial transport partner of an apically-expressed efflux transporter for the efficient translocation of physiological substrates into urine, some of which were suggested to be uremic toxins. However, our in vitro studies with MDCKII cells showed that upon transfection rat Oatp4c1 polarizes to the apical membrane. In this report, we validated the trafficking and function of Oatp4c1 in polarized cell systems as well as its subcellular …

Ceria-Engineered Nanomaterial Distribution In, And Clearance From, Blood: Size Matters, Mo Dan, Peng Wu, Eric A. Grulke, Uschi M. Graham, Jason M. Unrine, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

AIMS: Characterize different sized ceria-engineered nanomaterial (ENM) distribution in, and clearance from, blood (compared to the cerium ion) following intravenous infusion.

MATERIALS & METHODS: Cerium (Ce) was quantified in whole blood, serum and clot (the formed elements) up to 720 h.

RESULTS: Traditional pharmacokinetic modeling showed best fit for 5 nm ceria ENM and the cerium ion. Ceria ENMs larger than 5 nm were rapidly cleared from blood. After initially declining, whole blood 15 and 30 nm ceria increased (results that have not been well-described by traditional pharmacokinetic modeling). The cerium ion and 5 and 55 nm ceria did not …