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Low copulatory activity in selectively bred Sardinian alcohol-nonpreferring (sNP) relative to alcohol-preferring (sP) rats.

Karlsson O, Colombo G, Roman E - Ups. J. Med. Sci. (2015)

Bottom Line: There is a growing consensus that similar neural mechanisms are involved in the reinforcing properties of natural rewards, like food and sex, and drugs of abuse.Rat lines selectively bred for high and low oral alcohol intake and preference have been useful for understanding factors contributing to excessive alcohol intake and may constitute proper animal models for investigating the neurobiological basis of natural rewarding stimuli.Only minor differences between sP and Wistar rats were revealed.

View Article: PubMed Central - PubMed

Affiliation: Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institute , K8, 171 76 Stockholm , Sweden.

ABSTRACT

Background: There is a growing consensus that similar neural mechanisms are involved in the reinforcing properties of natural rewards, like food and sex, and drugs of abuse. Rat lines selectively bred for high and low oral alcohol intake and preference have been useful for understanding factors contributing to excessive alcohol intake and may constitute proper animal models for investigating the neurobiological basis of natural rewarding stimuli.

Methods: The present study evaluated copulatory behavior in alcohol and sexually naïve Sardinian alcohol-preferring (sP) and -nonpreferring (sNP) male rats in three consecutive copulatory behavior tests.

Results: The main finding was that, under the conditions used in this study, sNP rats were sexually inactive relative to sP rats. To gain more information about the sexual behavior in sP rats, Wistar rats were included as an external reference strain. Only minor differences between sP and Wistar rats were revealed.

Conclusions: The reason behind the low copulatory activity of sNP rats remains to be elucidated, but may in part be mediated by innate differences in brain transmitter systems. The comparison between sP and Wistar rats may also suggest that the inherent proclivity to excessive alcohol drinking in sP rats may mainly be dependent on its anxiolytic properties, as previously proposed, and not changes in the reward system.

No MeSH data available.


Related in: MedlinePlus

Latency to first mount (A), intromission (B), and ejaculation (C) in the three copulatory behavior tests in male sP (n = 15) and Wistar (n = 10) rats. The latency to first mount (A) in the third test is also shown in the insert for a better illustration of the difference between sP and Wistar rats. Values represent individual data points with the median value marked as a line, and in the insert values represent median and quartile range. * p < 0.05 comparing sP and Wistar rats (Mann–Whitney U test); # p < 0.05, ## p < 0.01 compared to the first copulatory behavior test within the respective group (Wilcoxon signed rank test).
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Figure 2: Latency to first mount (A), intromission (B), and ejaculation (C) in the three copulatory behavior tests in male sP (n = 15) and Wistar (n = 10) rats. The latency to first mount (A) in the third test is also shown in the insert for a better illustration of the difference between sP and Wistar rats. Values represent individual data points with the median value marked as a line, and in the insert values represent median and quartile range. * p < 0.05 comparing sP and Wistar rats (Mann–Whitney U test); # p < 0.05, ## p < 0.01 compared to the first copulatory behavior test within the respective group (Wilcoxon signed rank test).

Mentions: There were significant differences over time in sP and Wistar rats in latency to first mount (sP Friedman ANOVA (n = 15, df = 2) = 5.71, p = 0.058; Wistar Friedman ANOVA (n = 10, df = 2) = 15.08, p < 0.001), latency to first intromission (sP Friedman ANOVA n.s.; Wistar Friedman ANOVA (n = 10, df = 2) = 6.59, p < 0.05) and latency to first ejaculation (sP Friedman ANOVA (n = 15, df = 2) = 11.38, p < 0.01; Wistar Friedman ANOVA n.s.) (Figure 2). In Wistar rats, the latency to first mount and intromission, respectively, was significantly shorter in the second (mount Z = 2.29, p < 0.05; intromission Z = 2.02, p < 0.05) and third (mount Z = 2.80, p < 0.01; intromission Z = 2.55, p < 0.05) test relative to the first test. Likewise, in the third test, the latency to ejaculation was shorter (Z = 2.52, p < 0.05) when compared with the first test in sP rats. Moreover, when comparing sP and Wistar males, Wistar rats had shorter latency to the first mount in the third test (U = 37.5, p < 0.05; Figure 2A).


Low copulatory activity in selectively bred Sardinian alcohol-nonpreferring (sNP) relative to alcohol-preferring (sP) rats.

Karlsson O, Colombo G, Roman E - Ups. J. Med. Sci. (2015)

Latency to first mount (A), intromission (B), and ejaculation (C) in the three copulatory behavior tests in male sP (n = 15) and Wistar (n = 10) rats. The latency to first mount (A) in the third test is also shown in the insert for a better illustration of the difference between sP and Wistar rats. Values represent individual data points with the median value marked as a line, and in the insert values represent median and quartile range. * p < 0.05 comparing sP and Wistar rats (Mann–Whitney U test); # p < 0.05, ## p < 0.01 compared to the first copulatory behavior test within the respective group (Wilcoxon signed rank test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526873&req=5

Figure 2: Latency to first mount (A), intromission (B), and ejaculation (C) in the three copulatory behavior tests in male sP (n = 15) and Wistar (n = 10) rats. The latency to first mount (A) in the third test is also shown in the insert for a better illustration of the difference between sP and Wistar rats. Values represent individual data points with the median value marked as a line, and in the insert values represent median and quartile range. * p < 0.05 comparing sP and Wistar rats (Mann–Whitney U test); # p < 0.05, ## p < 0.01 compared to the first copulatory behavior test within the respective group (Wilcoxon signed rank test).
Mentions: There were significant differences over time in sP and Wistar rats in latency to first mount (sP Friedman ANOVA (n = 15, df = 2) = 5.71, p = 0.058; Wistar Friedman ANOVA (n = 10, df = 2) = 15.08, p < 0.001), latency to first intromission (sP Friedman ANOVA n.s.; Wistar Friedman ANOVA (n = 10, df = 2) = 6.59, p < 0.05) and latency to first ejaculation (sP Friedman ANOVA (n = 15, df = 2) = 11.38, p < 0.01; Wistar Friedman ANOVA n.s.) (Figure 2). In Wistar rats, the latency to first mount and intromission, respectively, was significantly shorter in the second (mount Z = 2.29, p < 0.05; intromission Z = 2.02, p < 0.05) and third (mount Z = 2.80, p < 0.01; intromission Z = 2.55, p < 0.05) test relative to the first test. Likewise, in the third test, the latency to ejaculation was shorter (Z = 2.52, p < 0.05) when compared with the first test in sP rats. Moreover, when comparing sP and Wistar males, Wistar rats had shorter latency to the first mount in the third test (U = 37.5, p < 0.05; Figure 2A).

Bottom Line: There is a growing consensus that similar neural mechanisms are involved in the reinforcing properties of natural rewards, like food and sex, and drugs of abuse.Rat lines selectively bred for high and low oral alcohol intake and preference have been useful for understanding factors contributing to excessive alcohol intake and may constitute proper animal models for investigating the neurobiological basis of natural rewarding stimuli.Only minor differences between sP and Wistar rats were revealed.

View Article: PubMed Central - PubMed

Affiliation: Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institute , K8, 171 76 Stockholm , Sweden.

ABSTRACT

Background: There is a growing consensus that similar neural mechanisms are involved in the reinforcing properties of natural rewards, like food and sex, and drugs of abuse. Rat lines selectively bred for high and low oral alcohol intake and preference have been useful for understanding factors contributing to excessive alcohol intake and may constitute proper animal models for investigating the neurobiological basis of natural rewarding stimuli.

Methods: The present study evaluated copulatory behavior in alcohol and sexually naïve Sardinian alcohol-preferring (sP) and -nonpreferring (sNP) male rats in three consecutive copulatory behavior tests.

Results: The main finding was that, under the conditions used in this study, sNP rats were sexually inactive relative to sP rats. To gain more information about the sexual behavior in sP rats, Wistar rats were included as an external reference strain. Only minor differences between sP and Wistar rats were revealed.

Conclusions: The reason behind the low copulatory activity of sNP rats remains to be elucidated, but may in part be mediated by innate differences in brain transmitter systems. The comparison between sP and Wistar rats may also suggest that the inherent proclivity to excessive alcohol drinking in sP rats may mainly be dependent on its anxiolytic properties, as previously proposed, and not changes in the reward system.

No MeSH data available.


Related in: MedlinePlus