Possible existence of Na(+)-coupled amino acid transport in the pigmented rabbit conjunctiva.
The objective of the present study was to determine whether Na(+)-amino acid cotransport contributed to the short-circuit current (ISC) in the isolated pigmented rabbit conjunctiva. Glycine, L-arginine, D-arginine, and L-glutamic acid were the amino acids tested, and bioelectric measurements were made in the Using chamber. The ISC was increased from 4% (L-glutamic acid) to 44% (L-arginine). The EC50 was 0.35 mM for glycine, 0.06 mM for L-arginine, 0.16 mM for D-arginine, and 1 mM for L-glutamic acid. No elevation in ISC was seen in the absence of Na+ in the mucosal bathing fluid. The above findings are consistent with the possible existence of a Na(+)-amino acid cotransport process on the apical side of the pigmented rabbit conjunctiva.
Kompella
U B
UB
Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles 90033, USA.
Kim
K J
KJ
Shiue
M H
MH
Lee
V H
VH
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism; D003228:Conjunctiva / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005998:Glycine / Q000378:metabolism; D017136:Ion Transport; D008297:Male; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*
D000596:Amino Acids; D001120:Arginine; D012964:Sodium; D005998:Glycine