PMID- 8176444
OWN - NLM
STAT- MEDLINE
DCOM- 19940609
LR  - 20171213
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 71
IP  - 2
DP  - 1994 Feb
TI  - GTP modulates run-up of whole-cell Ca2+ channel current in a Ca(2+)-dependent 
      manner.
PG  - 814-6
AB  - 1. Whole-cell voltage-clamp recordings were obtained from CA1 neurons acutely 
      dissociated from rat hippocampus to study the effects of guanosine 
      5'-triphosphate (GTP) on the gradual increase in Ca2+ channel current amplitude 
      that takes place over several minutes after breaking in to whole-cell mode 
      ("run-up"). 2. Including GTP (500 microM) in the patch pipette significantly 
      prolonged the duration of run-up of peak Ca2+ channel current to its maximum 
      value compared with controls without GTP when the recording solutions contained 
      Ca2+. On the other hand, GTP significantly enhanced run-up when Mg2+ and Ba2+ 
      were substituted for intracellular and extracellular Ca2+, respectively. 3. The 
      enhancement of run-up of the current in the Mg/Ba condition appeared to be due 
      both to an initial increase in current amplitude that was complete within 30 s 
      after break in and to a more rapid initial rate of run-up when compared with the 
      Ca2+ condition. GTP did not affect the absolute maximum amplitudes of the 
      currents in either Ca2+ or Ba2+ conditions. 4. We conclude that an early 
      GTP-dependent modulation of Ca2+ channel current is qualitatively altered, 
      depending on whether Ca2+ or Ba2+ is used as the charge carrier. Evidence of this 
      modulation is apparent within seconds after rupture of the membrane patch. 
      Conceivably, influences occurring during the period of "equilibration" with 
      electrode contents could alter subsequent regulatory steps.
FAU - Wagner, J J
AU  - Wagner JJ
AD  - Department of Physiology, School of Medicine, University of Maryland, Baltimore 
      21201.
FAU - Alger, B E
AU  - Alger BE
LA  - eng
GR  - NS-22010/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
RN  - 0 (Calcium Channels)
RN  - 86-01-1 (Guanosine Triphosphate)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium/*physiology
MH  - Calcium Channels/*physiology
MH  - Cells, Cultured
MH  - Guanosine Triphosphate/*physiology
MH  - Hippocampus/*physiology
MH  - Male
MH  - Membrane Potentials/physiology
MH  - Neurons/physiology
MH  - Rats
MH  - Synaptic Transmission/*physiology
EDAT- 1994/02/01 00:00
MHDA- 1994/02/01 00:01
CRDT- 1994/02/01 00:00
PHST- 1994/02/01 00:00 [pubmed]
PHST- 1994/02/01 00:01 [medline]
PHST- 1994/02/01 00:00 [entrez]
AID - 10.1152/jn.1994.71.2.814 [doi]
PST - ppublish
SO  - J Neurophysiol. 1994 Feb;71(2):814-6. doi: 10.1152/jn.1994.71.2.814.