Abstract
The characteristics of transmembrane currents evoked by 5-hydroxytryptamine (5-HT) in the neuroblastoma x Chinese hamster brain cell line NCB-20 and neuroblastoma clonal cell line N1E-115 have been studied under voltage-clamp conditions by the whole-cell recording and outside-out membrane patch modes of the patch-clamp technique. In 73% of NCB-20 cells examined (n = 221), and all N1E-115 cells studied (n = 80), 5-HT (10 μM) elicited a transient inward current at negative holding potentials, this being associated with an increase in membrane conductance. In both cell lines responses to 5-HT reversed in sign at a potential of approximately -2 mV and demonstrated inward rectification. The reversal potential of 5-HT-induced currents (E(5-HT)) recorded from either NCB-20 or N1E-115 cells was unaffected by total replacement of internal K+ by Cs+. In N1E-115 cells, reducing internal K+ concentration from 140 to 20 mM produced a positive shift in E(5-HT) of approximately 28 mV, whereas reducing external Na+ from 143 to 20 mM was associated with a negative shift in E(5-HT) of about 37 mV. A large reduction in internal Cl- concentration (from 144 to 6 mM) had little effect on E(5-HT). 5-HT-induced currents of NCB-20 cells were unaffected by methysergide (1 μM) or ketanserin (1 μM), but were reversibly antagonized by GR38032F (0.1-1.0 nM) with an IC50 of 0.25 nM. GR 38032F (0.3 nM) reduced 5-HT-induced currents in N1E-115 cells to approximately 26% of their control value. On outside-out membrane patches excised from both NCB-20 and N1E-115 cells, 5-HT induced small inward currents which could not be clearly resolved into discrete single channel events. Such responses were: (i) reversibly antagonized by GR 38032F (1 nM) (ii) reversed in sign at 0 mV, and (iii) subject to desensitization. Fluctuation analysis of inward currents evoked by 5-HT (1 μM) in N1E-115 cells suggests that 5-HT gates a channel with a conductance of approximately 310fS. Such a relatively small conductance could readily explain why the response of outside-out membrane patches to 5-HT cannot at present be resolved into clear single channel events.
| Original language | English |
|---|---|
| Pages (from-to) | 27-40 |
| Number of pages | 14 |
| Journal | British Journal of Pharmacology |
| Volume | 97 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - May 1989 |
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The properties of 5-HT3 receptors in clonal cell lines studied by patch-clamp techniques. / Lambert, J. J.; Peters, J. A.; Hales, T. G.; Dempster, J.
In: British Journal of Pharmacology, Vol. 97, No. 1, 05.1989, p. 27-40.Research output: Contribution to journal › Article
TY - JOUR
T1 - The properties of 5-HT3 receptors in clonal cell lines studied by patch-clamp techniques
AU - Lambert, J. J.
AU - Peters, J. A.
AU - Hales, T. G.
AU - Dempster, J.
PY - 1989/5
Y1 - 1989/5
N2 - The characteristics of transmembrane currents evoked by 5-hydroxytryptamine (5-HT) in the neuroblastoma x Chinese hamster brain cell line NCB-20 and neuroblastoma clonal cell line N1E-115 have been studied under voltage-clamp conditions by the whole-cell recording and outside-out membrane patch modes of the patch-clamp technique. In 73% of NCB-20 cells examined (n = 221), and all N1E-115 cells studied (n = 80), 5-HT (10 μM) elicited a transient inward current at negative holding potentials, this being associated with an increase in membrane conductance. In both cell lines responses to 5-HT reversed in sign at a potential of approximately -2 mV and demonstrated inward rectification. The reversal potential of 5-HT-induced currents (E(5-HT)) recorded from either NCB-20 or N1E-115 cells was unaffected by total replacement of internal K+ by Cs+. In N1E-115 cells, reducing internal K+ concentration from 140 to 20 mM produced a positive shift in E(5-HT) of approximately 28 mV, whereas reducing external Na+ from 143 to 20 mM was associated with a negative shift in E(5-HT) of about 37 mV. A large reduction in internal Cl- concentration (from 144 to 6 mM) had little effect on E(5-HT). 5-HT-induced currents of NCB-20 cells were unaffected by methysergide (1 μM) or ketanserin (1 μM), but were reversibly antagonized by GR38032F (0.1-1.0 nM) with an IC50 of 0.25 nM. GR 38032F (0.3 nM) reduced 5-HT-induced currents in N1E-115 cells to approximately 26% of their control value. On outside-out membrane patches excised from both NCB-20 and N1E-115 cells, 5-HT induced small inward currents which could not be clearly resolved into discrete single channel events. Such responses were: (i) reversibly antagonized by GR 38032F (1 nM) (ii) reversed in sign at 0 mV, and (iii) subject to desensitization. Fluctuation analysis of inward currents evoked by 5-HT (1 μM) in N1E-115 cells suggests that 5-HT gates a channel with a conductance of approximately 310fS. Such a relatively small conductance could readily explain why the response of outside-out membrane patches to 5-HT cannot at present be resolved into clear single channel events.
AB - The characteristics of transmembrane currents evoked by 5-hydroxytryptamine (5-HT) in the neuroblastoma x Chinese hamster brain cell line NCB-20 and neuroblastoma clonal cell line N1E-115 have been studied under voltage-clamp conditions by the whole-cell recording and outside-out membrane patch modes of the patch-clamp technique. In 73% of NCB-20 cells examined (n = 221), and all N1E-115 cells studied (n = 80), 5-HT (10 μM) elicited a transient inward current at negative holding potentials, this being associated with an increase in membrane conductance. In both cell lines responses to 5-HT reversed in sign at a potential of approximately -2 mV and demonstrated inward rectification. The reversal potential of 5-HT-induced currents (E(5-HT)) recorded from either NCB-20 or N1E-115 cells was unaffected by total replacement of internal K+ by Cs+. In N1E-115 cells, reducing internal K+ concentration from 140 to 20 mM produced a positive shift in E(5-HT) of approximately 28 mV, whereas reducing external Na+ from 143 to 20 mM was associated with a negative shift in E(5-HT) of about 37 mV. A large reduction in internal Cl- concentration (from 144 to 6 mM) had little effect on E(5-HT). 5-HT-induced currents of NCB-20 cells were unaffected by methysergide (1 μM) or ketanserin (1 μM), but were reversibly antagonized by GR38032F (0.1-1.0 nM) with an IC50 of 0.25 nM. GR 38032F (0.3 nM) reduced 5-HT-induced currents in N1E-115 cells to approximately 26% of their control value. On outside-out membrane patches excised from both NCB-20 and N1E-115 cells, 5-HT induced small inward currents which could not be clearly resolved into discrete single channel events. Such responses were: (i) reversibly antagonized by GR 38032F (1 nM) (ii) reversed in sign at 0 mV, and (iii) subject to desensitization. Fluctuation analysis of inward currents evoked by 5-HT (1 μM) in N1E-115 cells suggests that 5-HT gates a channel with a conductance of approximately 310fS. Such a relatively small conductance could readily explain why the response of outside-out membrane patches to 5-HT cannot at present be resolved into clear single channel events.
U2 - 10.1111/j.1476-5381.1989.tb11920.x
DO - 10.1111/j.1476-5381.1989.tb11920.x
M3 - Article
VL - 97
SP - 27
EP - 40
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
SN - 0007-1188
IS - 1
ER -