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Hyperactive when young, hypoactive and overweight when aged: connecting the dots in the story about locomotor activity, body mass, and aging in Trpv1 knockout mice.

Wanner SP, Garami A, Romanovsky AA - Aging (Albany NY) (2011)

Bottom Line: The present study solves this contradiction.By using two experimental paradigms, we show that aged Trpv1(-/-) mice have not an increased, but a decreased, locomotor activity, as compared to age-matched Trpv1(+/+) controls.We conclude that TRPV1 channels are involved in the regulation of both general locomotor activity and body mass in an age-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA.

ABSTRACT
We have recently found that, at a young age, transient receptor potential vanilloid-1 (Trpv1) knockout (-/-) mice have a higher locomotor activity than their wild-type littermates (+/+). We have also found that, with age, Trpv1(-/-) mice become substantially heavier than Trpv1(+/+) controls, thus forming a paradoxical association between locomotor hyperactivity and overweight. The present study solves this contradiction. By using two experimental paradigms, we show that aged Trpv1(-/-) mice have not an increased, but a decreased, locomotor activity, as compared to age-matched Trpv1(+/+) controls. We also confirm that aged Trpv1(-/-) mice are overweight. We conclude that TRPV1 channels are involved in the regulation of both general locomotor activity and body mass in an age-dependent manner.

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Related in: MedlinePlus

Aged Trpv1−/− mice have a higher body mass (P = 1 × 10−3) and a lower general locomotor activity (P < 1 × 10−7) than their genetically unaltered littermates. Group means (± SE) and individual data are shown. The locomotor activity was measured by telemetry during a 3-h period at the beginning of the inactive phase. The ambient temperature was 28°C.
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Figure 2: Aged Trpv1−/− mice have a higher body mass (P = 1 × 10−3) and a lower general locomotor activity (P < 1 × 10−7) than their genetically unaltered littermates. Group means (± SE) and individual data are shown. The locomotor activity was measured by telemetry during a 3-h period at the beginning of the inactive phase. The ambient temperature was 28°C.

Mentions: In addition to performing the measurements described above, we pooled together data from aged mice of both sexes, 14 Trpv1−/− and 14 Trpv1+/+, used in a different study (S. P. Wanner and A. A. Romanovsky, unpublished observations). These data are plotted in Figure 2. The age in the two groups was identical (42 ± 1 wk), but the Trpv1−/− were > 12% heavier than Trpv1+/+ (48 ± 1 g vs. 43 ± 1 g; P = 1 × 10−3). The locomotor activity of these animals was measured for 3 h during the inactive phase (6:00-9:00 AM). This time period was chosen, because it corresponded to the maximum difference in the locomotor activity between aged Trpv1−/− and Trpv1+/+ mice (Figure 1). The methods of animal preparation and measurements were identical to those used to produce the results presented in Figure 1, and the protocols were approved by the same committee. The 3-h measurements in the additional animals (Figure 2) have confirmed that the gross locomotor activity of aged Trpv1−/− mice is suppressed as compared to Trpv1+/+ controls (5 ± 1 and 14 ± 1 counts/min, respectively; P < 1 × 10−7).


Hyperactive when young, hypoactive and overweight when aged: connecting the dots in the story about locomotor activity, body mass, and aging in Trpv1 knockout mice.

Wanner SP, Garami A, Romanovsky AA - Aging (Albany NY) (2011)

Aged Trpv1−/− mice have a higher body mass (P = 1 × 10−3) and a lower general locomotor activity (P < 1 × 10−7) than their genetically unaltered littermates. Group means (± SE) and individual data are shown. The locomotor activity was measured by telemetry during a 3-h period at the beginning of the inactive phase. The ambient temperature was 28°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117461&req=5

Figure 2: Aged Trpv1−/− mice have a higher body mass (P = 1 × 10−3) and a lower general locomotor activity (P < 1 × 10−7) than their genetically unaltered littermates. Group means (± SE) and individual data are shown. The locomotor activity was measured by telemetry during a 3-h period at the beginning of the inactive phase. The ambient temperature was 28°C.
Mentions: In addition to performing the measurements described above, we pooled together data from aged mice of both sexes, 14 Trpv1−/− and 14 Trpv1+/+, used in a different study (S. P. Wanner and A. A. Romanovsky, unpublished observations). These data are plotted in Figure 2. The age in the two groups was identical (42 ± 1 wk), but the Trpv1−/− were > 12% heavier than Trpv1+/+ (48 ± 1 g vs. 43 ± 1 g; P = 1 × 10−3). The locomotor activity of these animals was measured for 3 h during the inactive phase (6:00-9:00 AM). This time period was chosen, because it corresponded to the maximum difference in the locomotor activity between aged Trpv1−/− and Trpv1+/+ mice (Figure 1). The methods of animal preparation and measurements were identical to those used to produce the results presented in Figure 1, and the protocols were approved by the same committee. The 3-h measurements in the additional animals (Figure 2) have confirmed that the gross locomotor activity of aged Trpv1−/− mice is suppressed as compared to Trpv1+/+ controls (5 ± 1 and 14 ± 1 counts/min, respectively; P < 1 × 10−7).

Bottom Line: The present study solves this contradiction.By using two experimental paradigms, we show that aged Trpv1(-/-) mice have not an increased, but a decreased, locomotor activity, as compared to age-matched Trpv1(+/+) controls.We conclude that TRPV1 channels are involved in the regulation of both general locomotor activity and body mass in an age-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA.

ABSTRACT
We have recently found that, at a young age, transient receptor potential vanilloid-1 (Trpv1) knockout (-/-) mice have a higher locomotor activity than their wild-type littermates (+/+). We have also found that, with age, Trpv1(-/-) mice become substantially heavier than Trpv1(+/+) controls, thus forming a paradoxical association between locomotor hyperactivity and overweight. The present study solves this contradiction. By using two experimental paradigms, we show that aged Trpv1(-/-) mice have not an increased, but a decreased, locomotor activity, as compared to age-matched Trpv1(+/+) controls. We also confirm that aged Trpv1(-/-) mice are overweight. We conclude that TRPV1 channels are involved in the regulation of both general locomotor activity and body mass in an age-dependent manner.

Show MeSH
Related in: MedlinePlus