<prompt> Ionic exchange in the corneal endothelium depends upon the metabolic rate. Which of the following can block Ionic exchange in corneal endothelium?Inhibition of anaerobic glycolysisActivation of anaerobic glycolysisActivation of cAMP phosphodiesterase inhibitorsInterference with electron chain transpo  <response>: A i.e. Inhibition of anaerobic glycolysis Endothelium provides a leaky barrier to aqueous humor by allowing molecules electrolytes of small size 2-3nm to penetrate through focal tight junctions maculae occludentes. This barrier function is Ca dependent. The delicate balance between fluid entering corneal stroma barrier function and fluid egressing 4-5 Ju1cm2hour the stroma Na K ATPase pump function maintain the corneal hydration at a fixed level of 78. Any change would cause corneal oedema. Corneal stroma contains glycosaminoglycans GAG which is the main cause of corneal hydration and swelling pressure 50mmHg. GAG has anionic charges 1t separation of one molecule from other making it a sponge like structure that can swell get hydrated The GAG anionic repulsion expands the tissue and sucks in fluid with equal pressure called imbibation pressure -30 mmHg Intraocular pressure 20 Swelling pressure 50 Imbibation pressure -30 Corneal oedema occurs if IOP exceeds SP as in glaucoma or if SP is low with normal 10P as in endothelial dystrophy. Endothelial pump is dependent on presence of Cl- HCO3- and can be slowed down by carbonic anhydrase inhibitor. Basolateral Na2HCO3 cotranspo, NaKV2C1- cotranspo, C1-HCO3- exchange, apical anion channels permeable to both Cl- HCO3- and carbonic anhydrase mediated CO2 diffusion mode of apical HCO3 flux are various anion transpo mechanisms in endothelium. When ATP produced by both glycolysis and aerobic respiration was inhibited by 0.1 mmoll iodoacetamide, the endothelial cells could not survive but when ATP synthesis alone by aerobic respiration was inhibited by 1.0 mmolL KCN, the endothelial cells survived for at least 1 week on the ATP produced by anaerobic glycolysisQ. 