Abstract
Originalsprog | Engelsk |
---|---|
Tidsskrift | Journal of Biological Chemistry |
Vol/bind | 274 |
Udgave nummer | 45 |
Sider (fra-til) | 31784-91 |
Antal sider | 7 |
ISSN | 0021-9258 |
Status | Udgivet - 1999 |
Bibliografisk note
Keywords: Adenosine Triphosphate; Animals; Electrophysiology; Female; Neuropeptides; Pancreatic Ducts; Polymerase Chain Reaction; Potassium Channel Blockers; Potassium Channels; RNA, Messenger; Rats; Rats, Wistar; Receptors, Purinergic P2; Uridine TriphosphateAdgang til dokumentet
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Purinoceptors Evoke Different Electrophysiological Responses in Pancreatic Ducts : P2Y INHIBITS K+ CONDUCTANCE, AND P2X STIMULATES CATION CONDUCTANCE. / Hede, S E; Amstrup, Jan; Christoffersen, Bettina C; Novak, I.
I: Journal of Biological Chemistry, Bind 274, Nr. 45, 1999, s. 31784-91.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Purinoceptors Evoke Different Electrophysiological Responses in Pancreatic Ducts
T2 - P2Y INHIBITS K+ CONDUCTANCE, AND P2X STIMULATES CATION CONDUCTANCE
AU - Hede, S E
AU - Amstrup, Jan
AU - Christoffersen, Bettina C
AU - Novak, I
N1 - Keywords: Adenosine Triphosphate; Animals; Electrophysiology; Female; Neuropeptides; Pancreatic Ducts; Polymerase Chain Reaction; Potassium Channel Blockers; Potassium Channels; RNA, Messenger; Rats; Rats, Wistar; Receptors, Purinergic P2; Uridine Triphosphate
PY - 1999
Y1 - 1999
N2 - In epithelia, extracellular nucleotides are often associated with regulation of ion transporters, especially Cl(-) channels. In this study, we investigated which purinoceptors are present in native pancreatic ducts and how they regulate ion transport. We applied whole-cell patch-clamp recordings, intracellular Ca(2+) and pH measurements, and reverse transcription-polymerase chain reaction (RT-PCR) analysis. The data show two types of purinoceptors and cellular responses. UTP and ATP produced large Ca(2+) transients, a decrease in intracellular pH, 8-10-mV depolarization of the membrane voltage, and a decrease in the whole-cell conductance. The membrane effects were due to closure of K(+) channels, as confirmed by dependence on extracellular K(+). UTP/ATP effects could be associated with P2Y(2) purinoceptors, and RT-PCR revealed mRNAs for P2Y(2) and P2Y(4) receptors. On the other hand, 2', 3'-O-4-benzoylbenzoyl-ATP induced Ca(2+) influx and approximately 20-mV depolarization of the membrane voltage with a concomitant increase in the whole-cell conductance. These effects were dependent on extracellular Na(+), not Cl(-), indicating opening of cation channels associated with P2X(7) purinoceptors. RT-PCR showed mRNAs for P2X(7) and P2X(4) receptors. In microperfused ducts, luminal (but not basolateral) ATP caused large depolarizations of membrane voltages recorded with microelectrodes, consistent with luminal localization of P2X(7) receptors. Thus, P2Y(2) (and possibly P2Y(4)) purinoceptors inhibit K(+) channels and may not support secretion in native ducts. P2X(7) (and possibly P2X(4)) receptors are associated with cation channels and may contribute to regulation of secretion.
AB - In epithelia, extracellular nucleotides are often associated with regulation of ion transporters, especially Cl(-) channels. In this study, we investigated which purinoceptors are present in native pancreatic ducts and how they regulate ion transport. We applied whole-cell patch-clamp recordings, intracellular Ca(2+) and pH measurements, and reverse transcription-polymerase chain reaction (RT-PCR) analysis. The data show two types of purinoceptors and cellular responses. UTP and ATP produced large Ca(2+) transients, a decrease in intracellular pH, 8-10-mV depolarization of the membrane voltage, and a decrease in the whole-cell conductance. The membrane effects were due to closure of K(+) channels, as confirmed by dependence on extracellular K(+). UTP/ATP effects could be associated with P2Y(2) purinoceptors, and RT-PCR revealed mRNAs for P2Y(2) and P2Y(4) receptors. On the other hand, 2', 3'-O-4-benzoylbenzoyl-ATP induced Ca(2+) influx and approximately 20-mV depolarization of the membrane voltage with a concomitant increase in the whole-cell conductance. These effects were dependent on extracellular Na(+), not Cl(-), indicating opening of cation channels associated with P2X(7) purinoceptors. RT-PCR showed mRNAs for P2X(7) and P2X(4) receptors. In microperfused ducts, luminal (but not basolateral) ATP caused large depolarizations of membrane voltages recorded with microelectrodes, consistent with luminal localization of P2X(7) receptors. Thus, P2Y(2) (and possibly P2Y(4)) purinoceptors inhibit K(+) channels and may not support secretion in native ducts. P2X(7) (and possibly P2X(4)) receptors are associated with cation channels and may contribute to regulation of secretion.
M3 - Journal article
C2 - 10542200
VL - 274
SP - 31784
EP - 31791
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 45
ER -