Camillo Peracchia | University of Rochester (original) (raw)

Camillo Peracchia

Retired researcher in the field of direct cell-cell communication via gap junction channels. Former teacher of respiratory physiology to 1st year medical students

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Papers by Camillo Peracchia

Elsevier eBooks, 1995

1. ABSTRACT The effects of ATP and arachidonic acid on junctional conductance (Gj) were studied i... more 1. ABSTRACT The effects of ATP and arachidonic acid on junctional conductance (Gj) were studied in Novikoff hepatoma cells, while monitoring either [Ca2+]i, with fura-2, or both membrane and junctional currents, with double whole-cell (DWCC) or double perforated patch clamp (DPPC). ATP (100 μM) increased [Ca2+]i to 400-1200 nM and in most cells decreased Gj by 30-40%. Simultaneously, an outward current developed, with a reversal potential of −80 mV at normal [K+]o that became 0 at 140 mM [K+]o, indicating that it is a Ca2+-activated K-current. Current peaks coincided with Gj minima, indicating that both phenomena result from an increase in [Ca2+]i. Arachidonic acid (AA, 20 μM, 20 s) had similar effects on [Ca2+]i and Gj. Internal BAPTA prevented Gj changes, suggesting Ca2+ dependence, but long exposures (20 μM AA, 1 min) caused uncoupling even with internal BAPTA, indicating that AA has both a Ca2+ mediated and a Ca2+ independent effect on coupling. However, Ca2+ dependent uncoupling had a much faster time course. BAPTA did not prevent uncoupling by oleic acid (OA) or halothane, suggesting that they act in Ca2+ independent way.

BENTHAM SCIENCE PUBLISHERS eBooks, Feb 7, 2014

Trends in Biochemical Sciences, Jul 1, 1978

BENTHAM SCIENCE PUBLISHERS eBooks, Feb 7, 2014

Springer eBooks, 1987

Many cell communities, in spite of the apparent structural individuality of their members, behave... more Many cell communities, in spite of the apparent structural individuality of their members, behave in some respects like syncytia, due to the existence of well-defined cell-to-cell channels of communication. Cooperative functions such as the synchronous spread of electrical impulse in heart, smooth muscle, and some areas of the nervous system, equilibration of ionic and metabolic pools, and coordinated responses of cell communities to hormonal or transmitter-mediated stimuli are among some of the many functions of direct cell-to-cell communication (cell coupling), a mechanism that enables tissues to respond to external and internal signals as integrated systems. Cell coupling represents the ability of cells to freely exchange with neighboring cells in direct contact with them, ions, metabolites, and messengers, while maintaining their individuality regarding macromolecules; the syncytiumlike feature being restricted to molecules smaller than M r 1000 (M r 2000 in certain invertebrates).