Abstract
Purpose: :
To measure the resting potential of the lens in rabbits (oryctolagus cuniculus).
Methods: :
We performed 40 experiments on rabbit’s lens. Immediately after decapitation the eyes were removed and the posterior pole and vitreous were excised. The anterior part of the eye was placed in a modified Ringer solution (RS) with the cornea downwards. The temperature in the chamber was set at 30°C by means of a thermostatic bath. RS composition in mM was: NaCl 100, KCl 6, CaCl 2, MgSO4 1, NaHPO4 1, NaHCO3 30 and glucose 20. Membrane potential was measured using microelectrode consisting of a thin recording electrode encased in a very fine-tipped glass pipette that was inserted through the posterior pole of the lens capsule. The microelectrode was connected via a voltmeter to a reference electrode that was immersed in the solution outside the lens. The voltmeter measures the voltage drop across the circuit caused by the membrane potential (mV). The signal was amplified and displayed on a Grass polygraph and chart recorder. The external electrode is outside the lens capsule. When the microelectrode crosses the lens capsule, whichever be its position, it sends a signal that is recorded as a negative potential in relation to the potential measured by the reference electrode. This gives the resting potential.
Results: :
The resting potential measured was 44.05 mV (SD 4.14), ranging from 33 mV to 53 mV. Brindley (1956) found a resting potencial of the rabbit's lens of 66 mV. This difference might be due to ionic content between the two sides of the lens capsule.
Conclusions: :
In this study the resting potencial of the rabbit's lens was equal to 44.05 mV (SD 4.14) ranging from 33 mV to 53 mV.
Keywords: pathology: experimental • crystallins • cataract