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PPL2ab neurons restore sexual responses in aged Drosophila males through dopamine.

Kuo SY, Wu CL, Hsieh MY, Lin CT, Wen RK, Chen LC, Chen YH, Yu YW, Wang HD, Su YJ, Lin CJ, Yang CY, Guan HY, Wang PY, Lan TH, Fu TF - Nat Commun (2015)

Bottom Line: We find that increasing DA levels in a subset of cells in the PPL2ab neuronal cluster is necessary and sufficient for increased sustained courtship in both young and aged male flies.Our results indicate that preventing the age-related decline in DA levels in PPL2ab neurons alleviates diminished courtship behaviours in male Drosophila.These results may provide the foundation for deciphering the circuitry involved in sexual motivation in the male Drosophila brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Chemistry, National Chi Nan University, 54561 Nantou, Taiwan.

ABSTRACT
Male sexual desire typically declines with ageing. However, our understanding of the neurobiological basis for this phenomenon is limited by our knowledge of the brain circuitry and neuronal pathways controlling male sexual desire. A number of studies across species suggest that dopamine (DA) affects sexual desire. Here we use genetic tools and behavioural assays to identify a novel subset of DA neurons that regulate age-associated male courtship activity in Drosophila. We find that increasing DA levels in a subset of cells in the PPL2ab neuronal cluster is necessary and sufficient for increased sustained courtship in both young and aged male flies. Our results indicate that preventing the age-related decline in DA levels in PPL2ab neurons alleviates diminished courtship behaviours in male Drosophila. These results may provide the foundation for deciphering the circuitry involved in sexual motivation in the male Drosophila brain.

No MeSH data available.


DA levels affect male courtship sustainment in aged flies.CS males were fed L-Dopa for 5 days beginning 35 days post-eclosion to increase DA levels. Behavioural assessments were carried out at 40 days post-eclosion. Significant differences were observed in the courtship index (a) and courtship bout length (b) in the flies fed 1 or 2 mg ml−1L-DOPA compared with the L-DOPA-naive controls. Each column represents the mean of 22 tests. (c–e) Schematic of the LexPR/LexAop inducible system; it was used to temporally increase DA levels in TH-GAL4-expressing neurons. Males aged 35 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 40-day-old time point (c). Significant differences were found in the courtship index (d) and courtship bout length (e) in the flies that carried the +/y;UAS-LexPR/LexAop-TH;+/TH-Gal4 or +/y;UAS-LexPR/+;TH-Gal4/LexAop-TH transgenes as compared with the flies of the same genetic background that did not receive RU486 treatment. Each bar represents the mean of 15 tests. (f–j) CS males at 5 days post-eclosion were fed 3IY, AMPT or Res for 5 days. Courtship behaviour analysis was conducted at the 10-day-old time point. There were significant differences in the courtship index (f) and courtship bout length (g) in the treated flies compared with non-treated controls. Each column represents the mean of 22 tests. (h–j) The LexPR/LexAop inducible system is diagrammed; it was used to temporally decrease DA levels in TH-Gal4 expressing neurons. Male flies aged 5 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 10-day-old time point (h). There were significant differences in the courtship index (i) and courtship bout length (j) in the flies that carried the +/y;UAS-LexPR/+;TH-Gal4/LexAop-thRNAi or +/y;UAS-LexPR/LexAop-thRNAi;+/TH-Gal4 transgenes compared with flies of the same genotype without RU486 treatment. Each column represents the mean of 15 tests. The error bars indicate+s.e.m. The means within a column followed by the same letters are not significantly different at the threshold of P<0.05 by two-way ANOVA followed by a Bonferroni multiple-comparisons test.
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f3: DA levels affect male courtship sustainment in aged flies.CS males were fed L-Dopa for 5 days beginning 35 days post-eclosion to increase DA levels. Behavioural assessments were carried out at 40 days post-eclosion. Significant differences were observed in the courtship index (a) and courtship bout length (b) in the flies fed 1 or 2 mg ml−1L-DOPA compared with the L-DOPA-naive controls. Each column represents the mean of 22 tests. (c–e) Schematic of the LexPR/LexAop inducible system; it was used to temporally increase DA levels in TH-GAL4-expressing neurons. Males aged 35 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 40-day-old time point (c). Significant differences were found in the courtship index (d) and courtship bout length (e) in the flies that carried the +/y;UAS-LexPR/LexAop-TH;+/TH-Gal4 or +/y;UAS-LexPR/+;TH-Gal4/LexAop-TH transgenes as compared with the flies of the same genetic background that did not receive RU486 treatment. Each bar represents the mean of 15 tests. (f–j) CS males at 5 days post-eclosion were fed 3IY, AMPT or Res for 5 days. Courtship behaviour analysis was conducted at the 10-day-old time point. There were significant differences in the courtship index (f) and courtship bout length (g) in the treated flies compared with non-treated controls. Each column represents the mean of 22 tests. (h–j) The LexPR/LexAop inducible system is diagrammed; it was used to temporally decrease DA levels in TH-Gal4 expressing neurons. Male flies aged 5 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 10-day-old time point (h). There were significant differences in the courtship index (i) and courtship bout length (j) in the flies that carried the +/y;UAS-LexPR/+;TH-Gal4/LexAop-thRNAi or +/y;UAS-LexPR/LexAop-thRNAi;+/TH-Gal4 transgenes compared with flies of the same genotype without RU486 treatment. Each column represents the mean of 15 tests. The error bars indicate+s.e.m. The means within a column followed by the same letters are not significantly different at the threshold of P<0.05 by two-way ANOVA followed by a Bonferroni multiple-comparisons test.

Mentions: To examine the effect of increased DA levels in aged flies on courtship sustainment, we fed 35-day-old male flies with L-3,4-dihydroxyphenylalanine (L-DOPA; the precursor for DA synthesis) for 5 days and tested courtship sustainment on day 40. Interestingly, courtship sustainment in flies that were fed L-DOPA was significantly upregulated in a dose-dependent manner, as compared with the control (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05). Correspondingly, the courtship index and courtship bout length were significantly increased in files that were fed L-DOPA (two-way analysis of variance (ANOVA) followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3a,b). To carry out a neuron-specific assay of the effects of increased DA expression, we induced extra TH production, and hence more DA synthesis, within DAergic neurons in 35-day-old males by feeding drug-sensitive mutant flies engineered with the LexPR/LexAop gene expression technique21 (UAS-LexPR;TH-Gal4>LexAop-TH) (Fig. 3c) 1.5 mM RU486 for 5 days. We found that the courtship index and courtship bout length of 40-day-old males were significantly increased in drug-treated flies (Fig. 3d,e). In contrast, when we inhibited DA function by feeding mature flies with α-methyl-p-tyrosine (AMPT) or 3-iodo-tyrosine (3IY) (both potent inhibitors of TH) and reserpine (Res; an inhibitor of vesicular monoamine transporter) for 5 days, we observed a marked reduction in the courtship index and courtship bout length (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3f,g ). In flies harbouring the same gene switch system, we disrupted DA production in young flies by RNAi-mediated knockdown of th transgene in DAergic neurons (UAS-LexPR;TH-Gal4>LexAop-thRNAi) (Fig. 3h), and this phenocopied the effects of DA inhibitor administration (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3i,j). Together, these data indicate that DA release from TH-Gal4-positive neurons is necessary and sufficient to promote strong male courtship behaviour.


PPL2ab neurons restore sexual responses in aged Drosophila males through dopamine.

Kuo SY, Wu CL, Hsieh MY, Lin CT, Wen RK, Chen LC, Chen YH, Yu YW, Wang HD, Su YJ, Lin CJ, Yang CY, Guan HY, Wang PY, Lan TH, Fu TF - Nat Commun (2015)

DA levels affect male courtship sustainment in aged flies.CS males were fed L-Dopa for 5 days beginning 35 days post-eclosion to increase DA levels. Behavioural assessments were carried out at 40 days post-eclosion. Significant differences were observed in the courtship index (a) and courtship bout length (b) in the flies fed 1 or 2 mg ml−1L-DOPA compared with the L-DOPA-naive controls. Each column represents the mean of 22 tests. (c–e) Schematic of the LexPR/LexAop inducible system; it was used to temporally increase DA levels in TH-GAL4-expressing neurons. Males aged 35 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 40-day-old time point (c). Significant differences were found in the courtship index (d) and courtship bout length (e) in the flies that carried the +/y;UAS-LexPR/LexAop-TH;+/TH-Gal4 or +/y;UAS-LexPR/+;TH-Gal4/LexAop-TH transgenes as compared with the flies of the same genetic background that did not receive RU486 treatment. Each bar represents the mean of 15 tests. (f–j) CS males at 5 days post-eclosion were fed 3IY, AMPT or Res for 5 days. Courtship behaviour analysis was conducted at the 10-day-old time point. There were significant differences in the courtship index (f) and courtship bout length (g) in the treated flies compared with non-treated controls. Each column represents the mean of 22 tests. (h–j) The LexPR/LexAop inducible system is diagrammed; it was used to temporally decrease DA levels in TH-Gal4 expressing neurons. Male flies aged 5 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 10-day-old time point (h). There were significant differences in the courtship index (i) and courtship bout length (j) in the flies that carried the +/y;UAS-LexPR/+;TH-Gal4/LexAop-thRNAi or +/y;UAS-LexPR/LexAop-thRNAi;+/TH-Gal4 transgenes compared with flies of the same genotype without RU486 treatment. Each column represents the mean of 15 tests. The error bars indicate+s.e.m. The means within a column followed by the same letters are not significantly different at the threshold of P<0.05 by two-way ANOVA followed by a Bonferroni multiple-comparisons test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
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f3: DA levels affect male courtship sustainment in aged flies.CS males were fed L-Dopa for 5 days beginning 35 days post-eclosion to increase DA levels. Behavioural assessments were carried out at 40 days post-eclosion. Significant differences were observed in the courtship index (a) and courtship bout length (b) in the flies fed 1 or 2 mg ml−1L-DOPA compared with the L-DOPA-naive controls. Each column represents the mean of 22 tests. (c–e) Schematic of the LexPR/LexAop inducible system; it was used to temporally increase DA levels in TH-GAL4-expressing neurons. Males aged 35 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 40-day-old time point (c). Significant differences were found in the courtship index (d) and courtship bout length (e) in the flies that carried the +/y;UAS-LexPR/LexAop-TH;+/TH-Gal4 or +/y;UAS-LexPR/+;TH-Gal4/LexAop-TH transgenes as compared with the flies of the same genetic background that did not receive RU486 treatment. Each bar represents the mean of 15 tests. (f–j) CS males at 5 days post-eclosion were fed 3IY, AMPT or Res for 5 days. Courtship behaviour analysis was conducted at the 10-day-old time point. There were significant differences in the courtship index (f) and courtship bout length (g) in the treated flies compared with non-treated controls. Each column represents the mean of 22 tests. (h–j) The LexPR/LexAop inducible system is diagrammed; it was used to temporally decrease DA levels in TH-Gal4 expressing neurons. Male flies aged 5 days were fed 1.5 mM RU486 (+) for 5 days and tested for the courtship behaviours at the 10-day-old time point (h). There were significant differences in the courtship index (i) and courtship bout length (j) in the flies that carried the +/y;UAS-LexPR/+;TH-Gal4/LexAop-thRNAi or +/y;UAS-LexPR/LexAop-thRNAi;+/TH-Gal4 transgenes compared with flies of the same genotype without RU486 treatment. Each column represents the mean of 15 tests. The error bars indicate+s.e.m. The means within a column followed by the same letters are not significantly different at the threshold of P<0.05 by two-way ANOVA followed by a Bonferroni multiple-comparisons test.
Mentions: To examine the effect of increased DA levels in aged flies on courtship sustainment, we fed 35-day-old male flies with L-3,4-dihydroxyphenylalanine (L-DOPA; the precursor for DA synthesis) for 5 days and tested courtship sustainment on day 40. Interestingly, courtship sustainment in flies that were fed L-DOPA was significantly upregulated in a dose-dependent manner, as compared with the control (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05). Correspondingly, the courtship index and courtship bout length were significantly increased in files that were fed L-DOPA (two-way analysis of variance (ANOVA) followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3a,b). To carry out a neuron-specific assay of the effects of increased DA expression, we induced extra TH production, and hence more DA synthesis, within DAergic neurons in 35-day-old males by feeding drug-sensitive mutant flies engineered with the LexPR/LexAop gene expression technique21 (UAS-LexPR;TH-Gal4>LexAop-TH) (Fig. 3c) 1.5 mM RU486 for 5 days. We found that the courtship index and courtship bout length of 40-day-old males were significantly increased in drug-treated flies (Fig. 3d,e). In contrast, when we inhibited DA function by feeding mature flies with α-methyl-p-tyrosine (AMPT) or 3-iodo-tyrosine (3IY) (both potent inhibitors of TH) and reserpine (Res; an inhibitor of vesicular monoamine transporter) for 5 days, we observed a marked reduction in the courtship index and courtship bout length (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3f,g ). In flies harbouring the same gene switch system, we disrupted DA production in young flies by RNAi-mediated knockdown of th transgene in DAergic neurons (UAS-LexPR;TH-Gal4>LexAop-thRNAi) (Fig. 3h), and this phenocopied the effects of DA inhibitor administration (two-way ANOVA followed by a Bonferroni multiple-comparisons test, P<0.05) (Fig. 3i,j). Together, these data indicate that DA release from TH-Gal4-positive neurons is necessary and sufficient to promote strong male courtship behaviour.

Bottom Line: We find that increasing DA levels in a subset of cells in the PPL2ab neuronal cluster is necessary and sufficient for increased sustained courtship in both young and aged male flies.Our results indicate that preventing the age-related decline in DA levels in PPL2ab neurons alleviates diminished courtship behaviours in male Drosophila.These results may provide the foundation for deciphering the circuitry involved in sexual motivation in the male Drosophila brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Chemistry, National Chi Nan University, 54561 Nantou, Taiwan.

ABSTRACT
Male sexual desire typically declines with ageing. However, our understanding of the neurobiological basis for this phenomenon is limited by our knowledge of the brain circuitry and neuronal pathways controlling male sexual desire. A number of studies across species suggest that dopamine (DA) affects sexual desire. Here we use genetic tools and behavioural assays to identify a novel subset of DA neurons that regulate age-associated male courtship activity in Drosophila. We find that increasing DA levels in a subset of cells in the PPL2ab neuronal cluster is necessary and sufficient for increased sustained courtship in both young and aged male flies. Our results indicate that preventing the age-related decline in DA levels in PPL2ab neurons alleviates diminished courtship behaviours in male Drosophila. These results may provide the foundation for deciphering the circuitry involved in sexual motivation in the male Drosophila brain.

No MeSH data available.