Question

Explain what would you expect if a drug which blocked the cation channel in the photoreceptive cells was applied to the left eye?

Answer 1

There are mainly two type of photoreceptors in the Eye

They are RODS AND CONES

RODS cell help in the scotopic or low light vision and cones cells help in color vision

A photoreceptor is activated when when the light hit on the photoreceptors

Rods cell get activated even when it is hit a single photon , that is rod cells are more sensitive

Cone cells need more number of Photons for the activation.

So, the stimuli for the activation photoreceptor is Light .

When the photoreceptor get activated it release the excitatory neurotransmitter called Glutamate. Glutamate will produce depolarization of the photoreceptor through the activation of the Na+/k+ Pump present on the membrane

When a drug inhibit the cation channel (Na+/k+ pump) , it is actually inhibiting the depolarization of the photoreceptor.

cation channel blocker inhibit the activation of a photoreceptor, so no further stimulation passed in to the ganglion cells of the Retina.

So, there is no action potential genration in the Optic nerve of the left eye , This result in the Blindness of the left eye.

So, this patient will have Left Monocular Vision Loss