Xenopus laevis Oocyte Recording Solutions

This document allows quick comparisons of recording solutions used by several investigators for patch clamping Xenopus laevis oocytes. Please refer to the cited references for complete descriptions of the solutions and the experimental designs for which they are appropriate. Non-referenced solutions are those used by the site author.

BATH SOLUTIONS

Modified Barth's Soln (MBSH), 500 mL (Yost et al, 1994).
500 mL, pH 7.0, 211 mOsm.
Titrate with NaOH. This solution may be used for storage of frog oocytes as well as a bath solution for voltage clamp experiments. Titrate the pH before adding divalents.
   MW  mM g
 NaCl 58.44 88 2.57
 KCl 75.55 1 0.04
 HEPES  238.31 10 1.19
 NaHCO3  84.00 2.4 0.10
 CaCl2 110.99 1 0.05
 Ca(NO3)2 164.10 1 0.082


Saline Bath Solution (Heinemann et al, 1992)
500 mL, pH 7.0, 255 mOsm
Titrate with NaOH
   MW  mM  g
 NaCl 58.44 115 3.36
 HEPES 238.31 10 1.19
 CaCl2 110.99 1.8 0.010

Depolarizing Bath Solution (Heinemann et al, Nature, 356, 441, 1992)
500 mL, pH 7.2, 256 mOsm
Titrate with KOH
   MW mM g
 NaCl 58.44 16 0.47
 KCl 74.55 100 3.73
 EGTA 380.4 1.8 0.34
 HEPES 238.31 10 1.19


Depolarizing Bath Solution (Ellinor et al, Nature, 363, 455, 1993)
500 mL, pH 7.2, 240 mOsm
Titrate with KOH.
   MW mM g
 K-aspartate 172.2 100 8.61
EGTA 380.4 10 1.90
HEPES 238.31 10 1.19


K-Methanesulfonate Depolarizing Solution for Frog Oocytes, 250 mL
250 mL, pH 7.4, 244 mOsm
Titrate with methanesulfonic acid.
   MW mM g
KOH 56.10 115 1.61
EGTA 380.4 1 0.09
HEPES 238.31 10 0.60
glucose* 180.16 3 0.13
MgCl2** 95.23 4 0.09

*Add more to adjust osmolarity (~5.3 g does the trick)


Hypertonic Saline for Removal of Vitelline Membrane, 500 mL (Ebihara, 1992)
500 mL, pH 7.2, 480 mOsm
Titrate with KOH. This saline is sufficiently hypertonic (~480 mOSm) to separate the vitelline membrane from the oocyte. However, the osmolarity can be pushed up to about 600 mOsm with additional K-aspartate to facilitate a faster and more complete separation without damage to the oocyte. Beware the oocyte that does not shrink after immersion in hypertonic saline as these generally have low resting membrane potentials when checked with two-electrode voltage clamp. They may be damaged or dead.
   MW mM g
 K-aspartate 172.2 200 17.22
KCl 74.55 20 0.75
MgCl2 95.23 1 0.05
 EGTA 380.4 10 1.90
HEPES 238.31 10 1.19



RECORDING ELECTRODE SOLUTIONS

Cell-AttachedRecording Electrode Soln for Na Channels (Heinemann et al, 1992)
500 mL, pH 7.2, 257 mOsm
Titrate with NaOH.
   MW mM g
 NaCl 58.44 100 2.92
KCl 74.55 16 0.60
CaCl2 110.99 1.8 0.10
HEPES 238.31 10 1.19


Cell-Attached Recording Electrode Solution for Ca Channels (Ellinor et al, 1993)
500 mL, pH 7.2, 365 mOsm
Titrate with KOH
   MW mM g
 BaCl2 208.25 115 11.97
HEPES 238.31 10 1.192


Recording Electrode Solution for Outside-Out Patches, 250 mL
250 mL, pH 7.4, 244 mOsm
Titrate with KOH
   MW mM g
 KCl 74.55 102 1.90
EGTA 380.4 10 0.95
HEPES 238.31 10 0.60
MgCl2* 95.23 4 0.09

*Improves seal formation (Hilgemann, 1995)


Recording Electrode Solution for NMDA Receptors, 250 mL
250 mL, pH 7.4, 244 mOsm
Titrate with NaOH. Add 10 µM glycine and 10 µM NMDA last.
   MW mM g
 NaCl 58.44 115 1.68
KCl 74.55 2.5 0.05
HEPES 238.31 10 0.60
 CaCl2 110.99 1.8 0.05



REFERENCES


Rudy and L.E. Iverson (eds.), In Methods in Enzymology, vol. 207. San Diego, Academic Press. p.376-380.

Heinemann et al. 1992. Nature, 356, 441.

Hilgemann, D.W. 1995. The giant membrane patch. In B. Sakmann and E. Neher (eds.),
Single-Channel Recording. Plenum Press, New York. p. 307-327.

Stühmer, W. & Parekh, A.B. 1995. Electrophysiological recordings from Xenopus oocytes. In B. Sakmann and E. Neher (eds.), Single Channel Recording, 2nd ed., New York, Plenum Press. p. 350-351.

Yost CS, Maestrone E. 1994. Anesth Analg, 78, 520-526.