Medicine and Health Sciences Commons^™

Neurophysiological Impact And Modeling-Independent Elucidation Of Inactivation Pathways In A-Type K+ Channels, J.D. Fineberg, David Ritter, Manuel Covarrubias

Department of Molecular Physiology and Biophysics Faculty Papers

Poster presented at Society for Neuroscience

Abstract:

A-type voltage-gated K⁺ channels auto-regulate their function by undergoing fast inactivation. Independent of molecular mechanisms, this inactivation can proceed after channel opening (open-state inactivation, OSI) or from a closed state prior to opening (closed-state inactivation, CSI). We hypothesize that the specific neurophysiological roles of A-type Kv channels depend on whether they undergo OSI, CSI or both (CSI+OSI). To explore these possibilities, we introduced Markov kinetic schemes of the A-type Kv4 conductance into a computational model of the hippocamcal CA1 neuron assuming either CSI or CSI+OSI and compared the properties of the somatic …

Increased Susceptibility To Metabolic Syndrome In Adult Offspring Of Angiotensin Type 1 Receptor Autoantibody-Positive Rats., Suli Zhang, Xi Zhang, Lihong Yang, Zi Yan, Li Yan, Jue Tian, Xiaoyu Li, Li Song, Li Wang, Xiaoli Yang, Ronghua Zheng, Wayne Bond Lau, Xinliang Ma, Huirong Liu

Department of Emergency Medicine Faculty Papers

Abstract Aims: Abnormal fetal and early postnatal growth is closely associated with adult-onset metabolic syndrome (MetS). However, the underlying etiological factors remain complex. The presence of the autoantibody against the angiotensin II type 1 receptor (AT1-Ab), a known risk factor for pre-eclampsia, may create a suboptimal intrauterine fetal environment. The current study investigated whether middle-aged offspring of AT1-Ab-positive mothers were prone to metabolic disorder development. Results: The AT1-Abs was detected in placental trophoblastic cells, capillary endothelium, and milk of pregnant rats actively immunized with the second extracellular loop of the AT1 receptor. AT1-Abs in newborn rats induced vasoconstriction, increased intracellular-free …

Perspectives On: Sgp Symposium On Mitochondrial Physiology And Medicine: Molecular Identities Of Mitochondrial Ca2+ Influx Mechanism: Updated Passwords For Accessing Mitochondrial Ca2+-Linked Health And Disease., Jin O-Uchi, Shi Pan, Shey-Shing Sheu

Center for Translational Medicine Faculty Papers

No abstract provided.

Essential Role Of Caveolin-3 In Adiponectin Signalsome Formation And Adiponectin Cardioprotection., Yajing Wang, Xiaoliang Wang, Jean-François Jasmin, Wayne Bond Lau, Rong Li, Yuexin Yuan, Wei Yi, Kurt Chuprun, Michael P. Lisanti, Walter J Koch, Erhe Gao, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

OBJECTIVE: Adiponectin (APN) system malfunction is causatively related to increased cardiovascular morbidity/mortality in diabetic patients. The aim of the current study was to investigate molecular mechanisms responsible for APN transmembrane signaling and cardioprotection.

METHODS AND RESULTS: Compared with wild-type mice, caveolin-3 knockout (Cav-3KO) mice exhibited modestly increased myocardial ischemia/reperfusion injury (increased infarct size, apoptosis, and poorer cardiac function recovery; P

CONCLUSIONS: Taken together, these results demonstrated for the first time that Cav-3 plays an essential role in APN transmembrane signaling and APN anti-ischemic/cardioprotective actions.

Glucose Decouples Intracellular Ca2+ Activity From Glucagon Secretion In Mouse Pancreatic Islet Alpha-Cells., Sylvain J Le Marchand, David W Piston

Farber Institute for Neuroscience Faculty Papers

The mechanisms of glucagon secretion and its suppression by glucose are presently unknown. This study investigates the relationship between intracellular calcium levels ([Ca(2+)](i)) and hormone secretion under low and high glucose conditions. We examined the effects of modulating ion channel activities on [Ca(2+)](i) and hormone secretion from ex vivo mouse pancreatic islets. Glucagon-secreting α-cells were unambiguously identified by cell specific expression of fluorescent proteins. We found that activation of L-type voltage-gated calcium channels is critical for α-cell calcium oscillations and glucagon secretion at low glucose levels. Calcium channel activation depends on K(ATP) channel activity but not on tetrodotoxin-sensitive Na(+) channels. …

Identification Of The Functional Binding Pocket For Compounds Targeting Small-Conductance Ca²⁺-Activated Potassium Channels., Miao Zhang, John M Pascal, Marcel Schumann, Roger S Armen, Ji-Fang Zhang

Department of Molecular Physiology and Biophysics Faculty Papers

Small- and intermediate-conductance Ca(2+)-activated potassium channels, activated by Ca(2+)-bound calmodulin, have an important role in regulating membrane excitability. These channels are also linked to clinical abnormalities. A tremendous amount of effort has been devoted to developing small molecule compounds targeting these channels. However, these compounds often suffer from low potency and lack of selectivity, hindering their potential for clinical use. A key contributing factor is the lack of knowledge of the binding site(s) for these compounds. Here we demonstrate by X-ray crystallography that the binding pocket for the compounds of the 1-ethyl-2-benzimidazolinone (1-EBIO) class is located at the calmodulin-channel interface. …