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Effects of cold exposure on behavioral and electrophysiological parameters related with hippocampal function in rats.

Elmarzouki H, Aboussaleh Y, Bitiktas S, Suer C, Artis AS, Dolu N, Ahami A - Front Cell Neurosci (2014)

Bottom Line: Meanwhile cold exposure did not affect the body weight (C: 221 ± 2.5 vs.S: 222 ± 1.7) but it impacts the adrenal gland relative weight (S: 27.1 ± 1.8 mg vs.C: 26.2 ± 1.4 mg).

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nutrition and Health, Department of Biology, Faculty of Science, Ibn Tofail University Kenitra, Morocco.

ABSTRACT

Aim: Behavioral and mental changes may occur in people exposed to cold stress by decreasing their work efficiency and their mental capacity while increasing the number of accidents on the job site. The goal of this study was to explore the effect of cold stress in spatial learning performance excitability and LTP.

Materials and methods: Three to four month old rats were randomly divided into four groups to form a control group and a cold stress group for each sex. The groups of cold stressed animals were placed in a cold room ambient temperature of 4°C for 2 h day. Adrenal glands and body weight (g) were recorded in control and stressed rats during the cold exposure. Spatial learning (acquisition phase) and memory (probe trial) were tested in the Morris water maze (MWM) immediately after daily exposure. Latency to locate the hidden platform, distance moved (DM), mean distance to platform, swim speed (SS) and time spent in the platform quadrant were compared between genders and treatments. Field potential recordings were made, under urethane anesthesia, from the dentate gyrus (DG) granule-cell layer, with stimulation of the medial perforant pathway 2 h after the probe trial. This study examined spatial memory as measured by MWM performance and hippocampal long-term potentiation (LTP) in the DG after exposure to cold in a repeated stress condition for 2 h/day for 5 days.

Results: The cold-exposed female rats needed less time to find the hidden platform on day 1 (43.0 ± 13.9 s vs. 63.2 ± 13.2 s), day 2 (18.2 ± 8.4 s vs. 40.9 ± 12.2 s) and on day 4 (8.0 ± 2.1 s vs. 17.2 ± 7.0 s) while cold-exposed male rats showed a decreased escape latency (EL) on day 1 only (37.3 ± 12.5 s vs. 75.4 ± 13.1 s). Cold-exposed male rats spent less time in the target quadrant (30.08 ± 6.11%) than the control male rats (37.33 ± 8.89%). Two hour cold exposure decreased population spike (PS) potentiation during both induction (218.3 ± 21.6 vs. 304.5 ± 18.8%) and maintenance intervals (193.9 ± 24.5 vs. 276.6 ± 25.4%) in male rats. Meanwhile cold exposure did not affect the body weight (C: 221 ± 2.5 vs. S: 222 ± 1.7) but it impacts the adrenal gland relative weight (S: 27.1 ± 1.8 mg vs. C: 26.2 ± 1.4 mg).

Conclusion: Overall, the results show that repeated cold exposure can selectively improve spatial learning in adult female rats, but impaired retention memory for platform location in male rats. It is possible that impaired LTP underlies some of the impaired retention memory caused by cold exposure in the male rats.

No MeSH data available.


Related in: MedlinePlus

Effects of cold exposure on acquisition performance in a task to find hidden platform in the water maze. All rats improved their ability as shown by decreasing escape latency (A) and distance moved (B) over training days. Control rats swam further away from the platform than experimental rats on the 1st and 2nd days as shown by mean distance to the platform (C). Swimming speed (D) did not change as a function of day. Measures per testing day represent the average of four trials of all animals in each group. Each symbol represents the mean ± SE of 10–12 rats. * represents significant difference between cold exposed and control male rats; • represents significant difference between exposed and control female rats. Cold-exposed male rats spent less time in seconds in the target quadrant than the control male rats. Similar retrieval performance was observed between cold-exposed and control female rats (E). Mean distance to platform in the probe trial was not affected by Treatment or Gender (F).
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Figure 2: Effects of cold exposure on acquisition performance in a task to find hidden platform in the water maze. All rats improved their ability as shown by decreasing escape latency (A) and distance moved (B) over training days. Control rats swam further away from the platform than experimental rats on the 1st and 2nd days as shown by mean distance to the platform (C). Swimming speed (D) did not change as a function of day. Measures per testing day represent the average of four trials of all animals in each group. Each symbol represents the mean ± SE of 10–12 rats. * represents significant difference between cold exposed and control male rats; • represents significant difference between exposed and control female rats. Cold-exposed male rats spent less time in seconds in the target quadrant than the control male rats. Similar retrieval performance was observed between cold-exposed and control female rats (E). Mean distance to platform in the probe trial was not affected by Treatment or Gender (F).

Mentions: In the MWM, which requires the integrity of the dorsal hippocampus, all groups successfully learned to find the hidden platform as shown by shortened ELs, DMs and MDPs (Day Effects: Fs(3,525) = 70.336, 78.515, 78.938; P < 0.001) over the four training days. The SS did not change within each group, showing similar motor ability (F(3,525) = 1.729; P > 0.05) during the training period. A Repeated-Measures ANOVA showed significant Treatment Effect on EL, DM, MDP and SS (Fs(1,172) = 33.662, 19.531, 47.709 and 30.026; Ps 0< 0.001). Significant Gender Effect was found on SS only (F(1,172) = 17.340; P = 0.001) and significant Interaction Effects were found on MDP (F(1,172) = 4.666; P = 0.032) and SS (F(1,172) = 20.786; P = 0.001). LSD post hoc tests showed that 2-h cold exposure decreased EL (Figure 2A; 75.4 ± 13.1 vs. 37.3 ± 12.5; P = 0.001), DM (Figure 2B; 914.6 ± 118.0 vs. 697.5 ± 183.8; P = 0.034), and MDP (Figure 2C; 58.2 ± 2.5 vs. 49.6 ± 4.1; P = 0.001) on the first day of training in male rats.


Effects of cold exposure on behavioral and electrophysiological parameters related with hippocampal function in rats.

Elmarzouki H, Aboussaleh Y, Bitiktas S, Suer C, Artis AS, Dolu N, Ahami A - Front Cell Neurosci (2014)

Effects of cold exposure on acquisition performance in a task to find hidden platform in the water maze. All rats improved their ability as shown by decreasing escape latency (A) and distance moved (B) over training days. Control rats swam further away from the platform than experimental rats on the 1st and 2nd days as shown by mean distance to the platform (C). Swimming speed (D) did not change as a function of day. Measures per testing day represent the average of four trials of all animals in each group. Each symbol represents the mean ± SE of 10–12 rats. * represents significant difference between cold exposed and control male rats; • represents significant difference between exposed and control female rats. Cold-exposed male rats spent less time in seconds in the target quadrant than the control male rats. Similar retrieval performance was observed between cold-exposed and control female rats (E). Mean distance to platform in the probe trial was not affected by Treatment or Gender (F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150461&req=5

Figure 2: Effects of cold exposure on acquisition performance in a task to find hidden platform in the water maze. All rats improved their ability as shown by decreasing escape latency (A) and distance moved (B) over training days. Control rats swam further away from the platform than experimental rats on the 1st and 2nd days as shown by mean distance to the platform (C). Swimming speed (D) did not change as a function of day. Measures per testing day represent the average of four trials of all animals in each group. Each symbol represents the mean ± SE of 10–12 rats. * represents significant difference between cold exposed and control male rats; • represents significant difference between exposed and control female rats. Cold-exposed male rats spent less time in seconds in the target quadrant than the control male rats. Similar retrieval performance was observed between cold-exposed and control female rats (E). Mean distance to platform in the probe trial was not affected by Treatment or Gender (F).
Mentions: In the MWM, which requires the integrity of the dorsal hippocampus, all groups successfully learned to find the hidden platform as shown by shortened ELs, DMs and MDPs (Day Effects: Fs(3,525) = 70.336, 78.515, 78.938; P < 0.001) over the four training days. The SS did not change within each group, showing similar motor ability (F(3,525) = 1.729; P > 0.05) during the training period. A Repeated-Measures ANOVA showed significant Treatment Effect on EL, DM, MDP and SS (Fs(1,172) = 33.662, 19.531, 47.709 and 30.026; Ps 0< 0.001). Significant Gender Effect was found on SS only (F(1,172) = 17.340; P = 0.001) and significant Interaction Effects were found on MDP (F(1,172) = 4.666; P = 0.032) and SS (F(1,172) = 20.786; P = 0.001). LSD post hoc tests showed that 2-h cold exposure decreased EL (Figure 2A; 75.4 ± 13.1 vs. 37.3 ± 12.5; P = 0.001), DM (Figure 2B; 914.6 ± 118.0 vs. 697.5 ± 183.8; P = 0.034), and MDP (Figure 2C; 58.2 ± 2.5 vs. 49.6 ± 4.1; P = 0.001) on the first day of training in male rats.

Bottom Line: Meanwhile cold exposure did not affect the body weight (C: 221 ± 2.5 vs.S: 222 ± 1.7) but it impacts the adrenal gland relative weight (S: 27.1 ± 1.8 mg vs.C: 26.2 ± 1.4 mg).

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nutrition and Health, Department of Biology, Faculty of Science, Ibn Tofail University Kenitra, Morocco.

ABSTRACT

Aim: Behavioral and mental changes may occur in people exposed to cold stress by decreasing their work efficiency and their mental capacity while increasing the number of accidents on the job site. The goal of this study was to explore the effect of cold stress in spatial learning performance excitability and LTP.

Materials and methods: Three to four month old rats were randomly divided into four groups to form a control group and a cold stress group for each sex. The groups of cold stressed animals were placed in a cold room ambient temperature of 4°C for 2 h day. Adrenal glands and body weight (g) were recorded in control and stressed rats during the cold exposure. Spatial learning (acquisition phase) and memory (probe trial) were tested in the Morris water maze (MWM) immediately after daily exposure. Latency to locate the hidden platform, distance moved (DM), mean distance to platform, swim speed (SS) and time spent in the platform quadrant were compared between genders and treatments. Field potential recordings were made, under urethane anesthesia, from the dentate gyrus (DG) granule-cell layer, with stimulation of the medial perforant pathway 2 h after the probe trial. This study examined spatial memory as measured by MWM performance and hippocampal long-term potentiation (LTP) in the DG after exposure to cold in a repeated stress condition for 2 h/day for 5 days.

Results: The cold-exposed female rats needed less time to find the hidden platform on day 1 (43.0 ± 13.9 s vs. 63.2 ± 13.2 s), day 2 (18.2 ± 8.4 s vs. 40.9 ± 12.2 s) and on day 4 (8.0 ± 2.1 s vs. 17.2 ± 7.0 s) while cold-exposed male rats showed a decreased escape latency (EL) on day 1 only (37.3 ± 12.5 s vs. 75.4 ± 13.1 s). Cold-exposed male rats spent less time in the target quadrant (30.08 ± 6.11%) than the control male rats (37.33 ± 8.89%). Two hour cold exposure decreased population spike (PS) potentiation during both induction (218.3 ± 21.6 vs. 304.5 ± 18.8%) and maintenance intervals (193.9 ± 24.5 vs. 276.6 ± 25.4%) in male rats. Meanwhile cold exposure did not affect the body weight (C: 221 ± 2.5 vs. S: 222 ± 1.7) but it impacts the adrenal gland relative weight (S: 27.1 ± 1.8 mg vs. C: 26.2 ± 1.4 mg).

Conclusion: Overall, the results show that repeated cold exposure can selectively improve spatial learning in adult female rats, but impaired retention memory for platform location in male rats. It is possible that impaired LTP underlies some of the impaired retention memory caused by cold exposure in the male rats.

No MeSH data available.


Related in: MedlinePlus