Linked Life Data

8551339

Source:http://linkedlifedata.com/resource/pubmed/id/8551339

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1996-2-22
pubmed:abstractText
Stimulus-secretion coupling in bovine chromaffin cells was investigated with whole-cell patch-clamp recordings and capacitance detection techniques to monitor exocytosis in response to trains of depolarizing pulses. Two kinetically discrete modes of exocytotic responses were observed. In one mode, the first depolarization of a train elicited a large increase in membrane capacitance (Cm; mean approximately 70 fF). This secretory mode was characterized by small Ca2+ requirements, relative insensitivity to the pipette Ca2+ chelator concentration, and rapid depletion of the secretory response. This mode of stimulus-secretion coupling was labile and was seen only in response to the first and, occasionally, the second stimulus train of whole-cell recordings. The second type of exocytotic response persisted for the remainder of the whole-cell recordings and consisted of two distinct phases. During the earliest pulses of a stimulus train, Ca2+ entry did not evoke Cm increases. Instead, Cm responses were elicited by later pulses, despite diminished Ca2+ entry per pulse caused by Ca2+ channel inactivation. The secretory phase was initiated after a specific "threshold" amount of Ca2+ had entered the cell, which was determined by the concentration, but not the binding kinetics, of the Ca2+ chelator in the pipette. In both the early and the secretory phases, the response of the cell was proportional to cumulative Ca2+ entry, regardless of current amplitude, pulse duration, or number of pulses. Threshold-type secretory kinetics has been described previously in peptide-secreting neurohypophysial (NHP) nerve terminals (Seward et al., 1995). Secretory kinetics with minimal Ca2+ requirements has not been observed in that preparation. Chromaffin cells appear to possess a broader repertoire of stimulus-secretion coupling modes than NHP terminals.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
553-62
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Kinetics of stimulus-coupled secretion in dialyzed bovine chromaffin cells in response to trains of depolarizing pulses.
pubmed:affiliation
Department of Anatomy and Neurobiology, Medical College of Pennsylvania, Philadelphia 19129, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't