Differential localization of putative amino acid receptors in taste buds of the channel catfish, Ictalurus punctatus.
J Comp Neurol
; 373(1): 129-38, 1996 Sep 09.
Article
em En
| MEDLINE
| ID: mdl-8876468
ABSTRACT
The taste system of catfish, having distinct taste receptor sites for L-alanine and L-arginine, is highly sensitive to amino acids. A previously described monoclonal antibody (G-10), which inhibits L-alanine binding to a partial membrane fraction (P2) derived from catfish (Ictalurus punctatus) taste epithelium, was found in Western blots to recognize a single band, at apparent MW of 113,000 D. This MW differs from the apparent MW for the presumed arginine receptor identified previously by PHA-E lectin affinity. In order to test whether PHA-E lectin actually reacts with the arginine-receptor, reconstituted membrane proteins partially purified by PHA-E affinity were used in artificial lipid bilayers. These reconstituted channels exhibited L-arginine-activated activity similar to that found in taste cell membranes. Accordingly, we utilized the PHA-E lectin and G-10 antibody as probes to differentially localize the L-alanine and L-arginine binding sites on the apical surface of catfish taste buds. Each probe labels numerous, small (0.5-1.0 micron) patches within the taste pore of each taste bud. This observation suggests that each bud is not tuned to a single taste substance, but contains putative receptor sites for both L-arginine and L-alanine. Further, analysis of double-labeled tissue reveals that the PHA-E and G-10 sites tend to be separate within each taste pore. These findings imply that in catfish, individual taste cells preferentially express receptors to either L-arginine or L-alanine. In addition, PHA-E binds to the apices of solitary chemoreceptor cells in the epithelium, indicating that this independent chemoreceptor system may utilize some receptor sites similar to those in taste buds.
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Base de dados:
MEDLINE
Assunto principal:
Arginina
/
Papilas Gustativas
/
Ictaluridae
/
Receptores de Aminoácido
/
Alanina
Idioma:
En
Ano de publicação:
1996
Tipo de documento:
Article