Abstract
Electrotonic current spread in the SA node of the rabbit was measured by means of hyperpolarizing current pulses (1 to 10 μA, 60 ms), which were injected intracellularly through a K+-perfused suction electrode. The pulses were applied at the beginning, middle or end of the diastolic depolarization phase. The resulting membrane potential change of nodal fibers was measured with microelectrodes. Space constants were calculated by fitting single exponential curves to the data. The input resistance (Rin) of fibers at different sites in the SA node was measured by means of a double barrel microelectrode (current pulses 5.5 to 11 nA, 60 ms) to detect a change in the internal resistance during the diastolic depolarization phase. During diastole the average electrotonic potential increased by 30% (P < 0.001), the increase of the space constant ranged from 9 to 183% (P < 0.05). Rin however, did not change during diastole. It is concluded that the electrotonic spread increased phase dependently, due to an increase of membrane resistance; the internal resistance was not phase dependent.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 415-427 |
| Number of pages | 13 |
| Journal | Journal of Molecular and Cellular Cardiology |
| Volume | 22 |
| Issue number | 4 |
| DOIs | |
| State | Published - 1990 |
| Externally published | Yes |
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Keywords
- Diastolic depolarization
- Electric coupling
- Electrotonus
- Input resistance
- Internal resistance
- Membrane resistance
- SA node
- Space constant
- Suction electrode
ASJC Scopus subject areas
- Molecular Biology
- Cardiology and Cardiovascular Medicine
Cite this
Phase dependency of electrotonic spread of hyperpolarizing current pulses in the rabbit sinoatrial node. / Duivenvoorden, Jeroen J.; Bouman, Lennart N.; Bukauskas, Feliksas F.; Opthof, Tobias; Jongsma, Habo J.
In: Journal of Molecular and Cellular Cardiology, Vol. 22, No. 4, 1990, p. 415-427.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phase dependency of electrotonic spread of hyperpolarizing current pulses in the rabbit sinoatrial node
AU - Duivenvoorden, Jeroen J.
AU - Bouman, Lennart N.
AU - Bukauskas, Feliksas F.
AU - Opthof, Tobias
AU - Jongsma, Habo J.
PY - 1990
Y1 - 1990
N2 - Electrotonic current spread in the SA node of the rabbit was measured by means of hyperpolarizing current pulses (1 to 10 μA, 60 ms), which were injected intracellularly through a K+-perfused suction electrode. The pulses were applied at the beginning, middle or end of the diastolic depolarization phase. The resulting membrane potential change of nodal fibers was measured with microelectrodes. Space constants were calculated by fitting single exponential curves to the data. The input resistance (Rin) of fibers at different sites in the SA node was measured by means of a double barrel microelectrode (current pulses 5.5 to 11 nA, 60 ms) to detect a change in the internal resistance during the diastolic depolarization phase. During diastole the average electrotonic potential increased by 30% (P < 0.001), the increase of the space constant ranged from 9 to 183% (P < 0.05). Rin however, did not change during diastole. It is concluded that the electrotonic spread increased phase dependently, due to an increase of membrane resistance; the internal resistance was not phase dependent.
AB - Electrotonic current spread in the SA node of the rabbit was measured by means of hyperpolarizing current pulses (1 to 10 μA, 60 ms), which were injected intracellularly through a K+-perfused suction electrode. The pulses were applied at the beginning, middle or end of the diastolic depolarization phase. The resulting membrane potential change of nodal fibers was measured with microelectrodes. Space constants were calculated by fitting single exponential curves to the data. The input resistance (Rin) of fibers at different sites in the SA node was measured by means of a double barrel microelectrode (current pulses 5.5 to 11 nA, 60 ms) to detect a change in the internal resistance during the diastolic depolarization phase. During diastole the average electrotonic potential increased by 30% (P < 0.001), the increase of the space constant ranged from 9 to 183% (P < 0.05). Rin however, did not change during diastole. It is concluded that the electrotonic spread increased phase dependently, due to an increase of membrane resistance; the internal resistance was not phase dependent.
KW - Diastolic depolarization
KW - Electric coupling
KW - Electrotonus
KW - Input resistance
KW - Internal resistance
KW - Membrane resistance
KW - SA node
KW - Space constant
KW - Suction electrode
UR - http://www.scopus.com/inward/record.url?scp=0025283094&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025283094&partnerID=8YFLogxK
U2 - 10.1016/0022-2828(90)91477-O
DO - 10.1016/0022-2828(90)91477-O
M3 - Article
C2 - 2388276
AN - SCOPUS:0025283094
VL - 22
SP - 415
EP - 427
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
SN - 0022-2828
IS - 4
ER -