Medicine and Health Sciences Commons^™

Morphine Exacerbates Hiv-1 Tat-Induced Cytokine Production In Astrocytes Through Convergent Effects On [Ca2+]I, Nf-Κb Trafficking And Transcription, Nazira El-Hage, Annadora J. Bruce-Keller, Tatiana Yakovleva, Igor Bazov, Georgy Bakalkin, Pamela E. Knapp, Kurt F. Hauser

Pharmacology and Toxicology Publications

Astroglia are key cellular sites where opiate drug signals converge with the proinflammatory effects of HIV-1 Tat signals to exacerbate HIV encephalitis. Despite this understanding, the molecular sites of convergence driving opiate-accelerated neuropathogenesis have not been deciphered. We therefore explored potential points of interaction between the signaling pathways initiated by HIV-1 Tat and opioids in striatal astrocytes. Profiling studies screening 152 transcription factors indicated that the nuclear factor-kappa B (NF-κB) subunit, c-Rel, was a likely candidate for Tat or Tat plus opiate-induced increases in cytokine and chemokine production by astrocytes. Pretreatment with the NF-κB inhibitor parthenolide provided evidence that Tat±morphine-induced …

Long Lasting Synchronization Of Calcium Oscillations By Cholinergic Stimulation In Isolated Pancreatic Islets, Min Zhang, Bernard Fendler, Bradford Peercy, Pranay Goel, Richard Bertram, Arthur Sherman, Leslie Satin

Pharmacology and Toxicology Publications

Abstract

Individual mouse pancreatic islets exhibit oscillations in [Ca²⁺]_i and insulin secretion in response to glucose in vitro, but how the oscillations of a million islets are coordinated within the human pancreas in vivo is unclear. Islet to islet synchronization is necessary, however, for the pancreas to produce regular pulses of insulin. To determine whether neurohormone release within the pancreas might play a role in coordinating islet activity, [Ca²⁺]_i changes in 4–6 isolated mouse islets were simultaneously monitored before and after a transient pulse of a putative synchronizing agent. The degree of synchronicity was …

Gap Junction Coupling And Calcium Waves In The Pancreatic Islet, Richard K.P. Benninger, Min Zhang, W. Steven Head, Leslie S. Satin, David W. Piston

Pharmacology and Toxicology Publications

Abstract

The pancreatic islet is a highly coupled, multicellular system that exhibits complex spatiotemporal electrical activity in response to elevated glucose levels. The emergent properties of islets, which differ from those arising in isolated islet cells, are believed to arise in part by gap junctional coupling, but the mechanisms through which this coupling occurs are poorly understood. To uncover these mechanisms, we have used both high-speed imaging and theoretical modeling of the electrical activity in pancreatic islets under a reduction in the gap junction mediated electrical coupling. Utilizing islets from a gap junction protein connexin 36 knockout mouse model together …