Abstracts - Association for Chemoreception Sciences

#P179 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
#P180 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
Energy supply in chemosensory cilia of olfactory receptor
neurons: Possible role of glycolysis
Pablo S Villar 1,2 , Juan G Reyes 1 , Juan Bacigalupo 2
1
Instituto de Química, Facultad de Ciencias, Pontificia Universidad
Católica de Valparaíso Valparaíso, Chile, 2 Departamento de Biología,
Facultad de Ciencias, Universidad de Chile Santiago, Chile
The chemosensory cilia of olfactory sensory neurons are long
and thin structures ( 60 x 0.2 µm) devoid of inner membranes,
specialized in odorant transduction. A cAMP pathway couples
the activation of odor receptors with the opening of cyclic
nucleotide-gated channels. During the odor response, the cilia
undergo high levels of ATP hydrolysis, as this nucleotide is
used by adenylyl cyclase, ATPases and kinases. Our estimates
of resting ATP level, ATP diffusion and consumption suggest
that the mitochondria, located near the base of the cilia, are
insufficient to sustain chemotransduction in the entire cilium
under intensive stimulation. Nuñez-Parra et al (Chem Senses
36:771-7802012) found glucose transporters in the sustentacular
cells of the olfactory epithelium. We hypothesize these cells
release glucose to the mucus, the cilia incorporated it from there
and utilize it by glycolysis, supplementing the required ATP.
To test this idea, we detected glycolytic enzymes by immunoblot
of a ciliary membrane preparation. Additionally, we measured
cilia and knob accumulation of a fluorescent deoxyglucose
analog when applied to mucosal side of the olfactory epithelium,
suggesting the apical presence of a glucose transporter. We
demonstrated by immunocytochemistry the ciliary location
of this transporter in isolated rat and toad olfactory neurons.
Additionally, field recordings (electroolfactogram) indicated that
inhibition of glycolysis and oxidative phosphorylation impairs
the odor response. Altogether, these results are consistent with a
dual supply of ATP in olfactory cilia, oxidative phosphorylation
and glycolysis. Acknowledgements: FONDECYT 1100682 (JB),
DI/VRIEA/PUCV (JGR)
Dietary calcium intake and ethnicity may contribute to
individual differences in taste perception.
Anna Voznesenskaya, Laura K. Alarcón, Michael G. Tordoff
Monell Chemical Senses Center Philadelphia, PA, USA
Calcium status affects preferences for calcium and sweet
solutions in rats and mice: calcium deficient rodents drink
more calcium solutions and avoid sweet compounds. Moreover,
preference for calcium is inversely correlated with preference
for sweet compounds in calcium replete mice. However, little is
known about the relationships between calcium status and taste
perception in humans. Here we measured detection thresholds
for CaCl 2
and sucrose, and assessed intensity and taste quality
ratings of CaCl 2
, sucrose, NaCl, QHCl and citric acid in an
ethnically diverse group of people in relation to dietary calcium
intake. African-Americans had significantly higher detection
thresholds than Caucasians for both CaCl 2
and sucrose. They
rated 25 mM CaCl 2
as predominantly sour significantly more
frequently than Caucasians. There was no relationship between
dietary calcium intake and CaCl 2
detection threshold. In African-
Americans but not Caucasians sucrose detection threshold was
inversely correlated with dietary calcium levels (Spearman’s
rho = - 0.93, p