Age-Related Changes in Mouse Taste Bud Morphology, Hormone Expression, and Taste Responsivity

Abstract

Normal aging is a complex process that affects every organ system in the body, including the taste system. Thus, we investigated the effects of the normal aging process on taste bud morphology, function, and taste responsivity in male mice at 2, 10, and 18 months of age. The 18-month-old animals demonstrated a significant reduction in taste bud size and number of taste cells per bud compared with the 2- and 10-month-old animals. The 18-month-old animals exhibited a significant reduction of protein gene product 9.5 and sonic hedgehog immunoreactivity (taste cell markers). The number of taste cells expressing the sweet taste receptor subunit, T1R3, and the sweet taste modulating hormone, glucagon-like peptide-1, were reduced in the 18-month-old mice. Concordant with taste cell alterations, the 18-month-old animals demonstrated reduced sweet taste responsivity compared with the younger animals and the other major taste modalities (salty, sour, and bitter) remained intact.

Long-Term Artificial Sweetener Acesulfame Potassium Treatment Alters Neurometabolic Functions in C57BL/6J Mice

“…Mice were tested as previously described [82]. Briefly, mice were placed in the gustometer for 25 mins, and stimuli were presented in random order for 5 sec trials that were initiated by the mouse licking the stimulus spouts (ACK was presented as a concentration range of 0.2, 1.0, 10, 25, 50, 75, 100 mM or water).…”

Altered Lipid and Salt Taste Responsivity in Ghrelin and GOAT Null Mice

“…Behavioral assessment of taste responsivity was performed as previously described [33], [34], [35]. All taste testing took place during daylight hours, and all mice were habituated to the laboratory environment for 30 minutes each day prior to the initiation of taste testing.…”

“…Test stimuli consisted of various concentrations of sucrose (25, 75, 150, 300, 600 and 1000 mM; Fisher Scientific, Atlanta, GA), sodium chloride (NaCl:15, 100, 300, 500, 600 and 1000 mM; Sigma), denatonium benzoate (DB: 0.001, 0.01, 0.1, 0.3, 1 and 3 mM; Sigma), citric acid (CA: 0.1, 0.5, 1, 3, 5, 10, 20, 30, and 100 mM; Fisher Scientific), and intralipid (0.1%, 1%, 5%, 10%, and 20%: Sigma). Brief-access taste testing took place in a Davis MS-160 gustometer (DiLog Instruments, Tallahassee, FL) as previously described [35]. Brief-access procedures minimize post-ingestive effects that may confound other assays such as intake tests or 2-bottle taste tests.…”

Amitriptyline Improves Motor Function via Enhanced Neurotrophin Signaling and Mitochondrial Functions in the Murine N171-82Q Huntington Disease Model

“…The same image exposure time was applied to sections from all treatment groups within a given comparison. Following antigen retrieval with a 1ϫ citrate buffer (Biogenex, San Ramon, CA) at 98°C for 20 min, immunofluorescence analyses were performed as described previously (37). Brain sections were blocked in 5% bovine serum albumin (BSA; Sigma) and 0.1% Tween 20 in 1ϫ Tris-buffered saline (TBS) (pH 7.4) for 1 h at room temperature, followed by incubation in a primary antibody ( Stereological Analysis-The optical fractionator probe of Stereoinvestigator software (MicroBrightField, Inc., Williston, VT) was used to obtain an unbiased estimate of NeuN-positive neurons in the striatum and associated cortex (located in the same section with striatum) as per the atlas of the mouse brain by Franklin and Paxinos (38).…”