Lack of gurmarin sensitivity of sweet taste receptors innervated by
the glossopharyngeal nerve in c57bl mice.
YNinomiya, Yuzo, Masashi Inoue, Toshiaki Imoto, and Kiyoto Nakashima .
Department of Oral Physiology, and Chemistry, Asahi University
School of Dentistry, Hozumi, Motosu, Gifu 501-02, Japan, Department
of Physiology, Tottori University School of Medicine, Yonago, Tottori
683, Japan
APStracts 3:0436R, 1996.
Effects of a sweet response inhibitor, gurmarin, on responses of the
chorda tympani and glossopharyngeal nerves were studied in the
C57BL/KsJ strain of mice. The lingual application of gurmarin at 3.0
g / ml (0.7M) or more significantly suppressed chorda tympani
responses to 0.5 M sucrose, as previously reported. The magnitude of
gurmarin inhibition of the chorda tympani responses reached a plateau
(about 45 % of control) at 50 g / ml (11.9M). In contrast, no such
gurmarin inhibition of sucrose responses was observed in the
glossopharyngeal nerve even at 100 g / ml (23.8 M). The lingual
application of a proteolytic enzyme, pronase, suppressed sucrose
responses to less than 20 % of control in both chorda tympani and
glossopharyngeal nerves. These results suggest differential
sensitivity to gurmarin by sweet taste receptors innervated by the
chorda tympani and the glossopharyngeal nerves. The former apparently
possess gurmarin sensitivity, whereas most of the latter may be
lacking sensitivity.
Received 13 September 1996; accepted in final form 3 December
1996.
APS Manuscript Number R549-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996