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Yuji Mori - One of the best experts on this subject based on the ideXlab platform.
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Alarm Pheromone does not modulate 22-kHz calls in male rats
Physiology & behavior, 2016Co-Authors: Hiromi Muyama, Yasushi Kiyokawa, Yukari Takeuchi, Hideaki Inagaki, Yuji MoriAbstract:Rats are known to emit a series of ultrasonic vocalizations, termed 22-kHz calls, when exposed to distressing stimuli. Pharmacological studies have indicated that anxiety mediates 22-kHz calls in distressed rats. We previously found that exposure to the rat Alarm Pheromone increases anxiety in rats. Therefore, we hypothesized that the Alarm Pheromone would increase 22-kHz calls in Pheromone-exposed rats. Accordingly, we tested whether exposure to the Alarm Pheromone induced 22-kHz calls, as well as whether the Alarm Pheromone increased 22-kHz calls in response to an aversive conditioned stimulus (CS). Rats were first fear-conditioned to an auditory and contextual CS. On the following day, the rats were either exposed to the Alarm Pheromone or a control odor that was released from the neck region of odor-donor rats. Then, the rats were re-exposed to the aversive CS. The Alarm Pheromone neither induced 22-kHz calls nor increased 22-kHz calls in response to the aversive CS. In contrast, the control odor unexpectedly reduced the total number and duration of 22-kHz calls elicited by the aversive CS, as well as the duration of freezing. These results suggest that the Alarm Pheromone does not affect 22-kHz calls in rats. However, we may have found evidence for an appeasing olfactory signal, released from the neck region of odor-donor rats.
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neural correlates underlying naloxone induced amelioration of sexual behavior deterioration due to an Alarm Pheromone
Frontiers in Neuroscience, 2015Co-Authors: Tatsuya Kobayashi, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Sexual behavior is suppressed by various types of stressors. We previously demonstrated that an Alarm Pheromone released by stressed male Wistar rats is a stressor to other rats, increases the number of mounts needed for ejaculation, and decreases the hit rate (described as the number of intromissions/sum of the mounts and intromissions). This deterioration in sexual behavior was ameliorated by pretreatment with the opioid receptor antagonist naloxone. However, the neural mechanism underlying this remains to be elucidated. Here, we examined Fos expression in 31 brain regions of Pheromone-exposed rats and naloxone-pretreated Pheromone-exposed rats 60 min after 10 intromissions. As previously reported, the Alarm Pheromone increased the number of mounts and decreased the hit rate. In addition, Fos expression was increases in the anterior medial division, anterior lateral division and posterior division of the bed nucleus of the stria terminalis, parvocellular part of the paraventricular nucleus of the hypothalamus, arcuate nucleus, dorsolateral and ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Fos expression decreased in the magnocellular part of the paraventricular nucleus of the hypothalamus. Pretreatment with naloxone blocked the Pheromone-induced changes in Fos expression in the magnocellular part of the paraventricular nucleus of the hypothalamus, ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Based on these results, we hypothesize that the Alarm Pheromone deteriorated sexual behavior by activating the ventrolateral periaqueductal gray-nucleus paragigantocellularis cluster and suppressing the magnocellular part of the paraventricular nucleus of the hypothalamus via the opioidergic pathway.
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Alarm Pheromone Is Detected by the Vomeronasal Organ in Male Rats
Chemical senses, 2013Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Yuka Kodama, Takahiro Kubota, Yuji MoriAbstract:It is widely known that a stressed animal releases specific Pheromones, possibly for Alarming nearby conspecifics. We previously investigated an Alarm Pheromone in male rats and found that this Alarm Pheromone evokes several responses, including increases in the defensive and risk assessment behaviors in a modified open-field test, and enhancement of the acoustic startle reflex. However, the role of the vomeronasal organ in these Pheromone effects remains unclear. To clarify this point, vomeronasal organ-excising or sham surgeries were performed in male rats for use in 2 experimental models, after which they were exposed to Alarm Pheromone. We found that the vomeronasal organ-excising surgery blocked the effects of this Alarm Pheromone in both the modified open-field test and acoustic startle reflex test. In addition, the results of habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb suggested that the vomeronasal organ-excising surgery completely ablated the vomeronasal organ while preserving the functioning of the main olfactory system. From the above results, we showed that the vomeronasal organ plays an important role in Alarm Pheromone effects in the modified open-field test and acoustic startle reflex test.
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Naloxone blocks the deterioration of male sexual behavior induced by Alarm Pheromone in rats.
Journal of Veterinary Medical Science, 2013Co-Authors: Tatsuya Kobayashi, Sayaka Arata, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Previously, we have demonstrated that the Alarm Pheromone deteriorates sexual behavior in male rats, which was blocked by pretreatment with a corticotrophin-releasing hormone (CRH) antagonist. Studies have shown that an opioid antagonist blocked the deterioration of male sexual behavior following intracerebroventricular administration of CRH. Therefore, possibly, the Pheromone effects could also be mediated by the opioid system. In this study, we pretreated rats with naloxone, an opioid receptor antagonist, and examined the following sexual behavior modulations in male rats that were exposed to the Alarm Pheromone. Naloxone blocked the deterioration of sexual behavior in a dose-dependent manner. On the basis of these data and the results of the previous study, we conclude that the Alarm Pheromone activates the CRH system, which then activates the opioid system, to deteriorate male sexual behavior.
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c-Fos expression during the modulation of sexual behavior by an Alarm Pheromone.
Behavioural brain research, 2012Co-Authors: Tatsuya Kobayashi, Sayaka Arata, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:We previously demonstrated that an Alarm Pheromone released by male Wistar rats evokes several physiological and behavioral responses in other rats. In addition to these responses, the Alarm Pheromone increased the number of mounts needed for an ejaculation and decreased the hit rate (number of intromissions/sum of the mounts and intromissions). These effects were blocked by pretreatment by a corticotropin releasing hormone (CRH) receptor antagonist. However, the neural mechanisms underlying the modulation of sexual behavior by this Pheromone remain unknown. In this study, we measured c-Fos expression in 22 brain sites in Pheromone-exposed male rats 60 min after their first ejaculation. The paraventricular nucleus was double-stained for c-Fos and CRH to determine which neurons were activated by the Pheromone. The Alarm Pheromone increased the number of mounts, decreased the hit rate, and increased the number of cells double-labeled for c-Fos and CRH in the paraventricular nucleus. These results indicate that the Alarm Pheromone is a stressor. Pheromone-exposed rats also showed significantly increased c-Fos expression in the anterior division medial group, anterior division lateral group, and posterior division of the bed nucleus of the stria terminalis, the anterior part of the medial and the basolateral region of the amygdala, and the nucleus paragigantocellularis. Based on these results and previous findings, we propose that the Alarm Pheromone modifies sexual behavior by inducing CRH release that indirectly activates the nucleus paragigantocellularis.
Yasushi Kiyokawa - One of the best experts on this subject based on the ideXlab platform.
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Alarm Pheromone does not modulate 22-kHz calls in male rats
Physiology & behavior, 2016Co-Authors: Hiromi Muyama, Yasushi Kiyokawa, Yukari Takeuchi, Hideaki Inagaki, Yuji MoriAbstract:Rats are known to emit a series of ultrasonic vocalizations, termed 22-kHz calls, when exposed to distressing stimuli. Pharmacological studies have indicated that anxiety mediates 22-kHz calls in distressed rats. We previously found that exposure to the rat Alarm Pheromone increases anxiety in rats. Therefore, we hypothesized that the Alarm Pheromone would increase 22-kHz calls in Pheromone-exposed rats. Accordingly, we tested whether exposure to the Alarm Pheromone induced 22-kHz calls, as well as whether the Alarm Pheromone increased 22-kHz calls in response to an aversive conditioned stimulus (CS). Rats were first fear-conditioned to an auditory and contextual CS. On the following day, the rats were either exposed to the Alarm Pheromone or a control odor that was released from the neck region of odor-donor rats. Then, the rats were re-exposed to the aversive CS. The Alarm Pheromone neither induced 22-kHz calls nor increased 22-kHz calls in response to the aversive CS. In contrast, the control odor unexpectedly reduced the total number and duration of 22-kHz calls elicited by the aversive CS, as well as the duration of freezing. These results suggest that the Alarm Pheromone does not affect 22-kHz calls in rats. However, we may have found evidence for an appeasing olfactory signal, released from the neck region of odor-donor rats.
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temporary inactivation of the anterior part of the bed nucleus of the stria terminalis blocks Alarm Pheromone induced defensive behavior in rats
Frontiers in Neuroscience, 2015Co-Authors: Tino Breitfeld, Yasushi Kiyokawa, Yukari Takeuchi, Hideaki Inagaki, Johann E A Bruning, Markus FendtAbstract:Rats emit an Alarm Pheromone in threatening situations. Exposure of rats to this Alarm Pheromone induces defensive behaviors, such as head out behavior, and increases c-Fos expression in brain areas involved in the mediation of defensive behaviors. One of these brain areas is the anterior bed nucleus of the stria terminalis (aBNST). The goal of the present study was to investigate if pharmacological inactivation of the aBNST by local microinjections of the GABAA receptor-agonist muscimol modulates Alarm Pheromone-induced defensive behaviors. We first established the behavioral paradigm of Alarm Pheromone-induced defensive behaviors in Sprague-Dawley rats in our laboratory. In a second experiment, we inactivated the aBNST, then exposed rats to one of four different odors (neck odor, female urine, Alarm Pheromone, fox urine) and tested the effects of the aBNST inactivation on the behavior in response to these odors. Our data show that temporary inactivation of the aBNST blocked head out behavior in response to the Alarm Pheromone. This indicates that the aBNST plays an important role in the mediation of the Alarm Pheromone-induced defensive behavior in rats.
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neural correlates underlying naloxone induced amelioration of sexual behavior deterioration due to an Alarm Pheromone
Frontiers in Neuroscience, 2015Co-Authors: Tatsuya Kobayashi, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Sexual behavior is suppressed by various types of stressors. We previously demonstrated that an Alarm Pheromone released by stressed male Wistar rats is a stressor to other rats, increases the number of mounts needed for ejaculation, and decreases the hit rate (described as the number of intromissions/sum of the mounts and intromissions). This deterioration in sexual behavior was ameliorated by pretreatment with the opioid receptor antagonist naloxone. However, the neural mechanism underlying this remains to be elucidated. Here, we examined Fos expression in 31 brain regions of Pheromone-exposed rats and naloxone-pretreated Pheromone-exposed rats 60 min after 10 intromissions. As previously reported, the Alarm Pheromone increased the number of mounts and decreased the hit rate. In addition, Fos expression was increases in the anterior medial division, anterior lateral division and posterior division of the bed nucleus of the stria terminalis, parvocellular part of the paraventricular nucleus of the hypothalamus, arcuate nucleus, dorsolateral and ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Fos expression decreased in the magnocellular part of the paraventricular nucleus of the hypothalamus. Pretreatment with naloxone blocked the Pheromone-induced changes in Fos expression in the magnocellular part of the paraventricular nucleus of the hypothalamus, ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Based on these results, we hypothesize that the Alarm Pheromone deteriorated sexual behavior by activating the ventrolateral periaqueductal gray-nucleus paragigantocellularis cluster and suppressing the magnocellular part of the paraventricular nucleus of the hypothalamus via the opioidergic pathway.
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Alarm Pheromone Is Detected by the Vomeronasal Organ in Male Rats
Chemical senses, 2013Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Yuka Kodama, Takahiro Kubota, Yuji MoriAbstract:It is widely known that a stressed animal releases specific Pheromones, possibly for Alarming nearby conspecifics. We previously investigated an Alarm Pheromone in male rats and found that this Alarm Pheromone evokes several responses, including increases in the defensive and risk assessment behaviors in a modified open-field test, and enhancement of the acoustic startle reflex. However, the role of the vomeronasal organ in these Pheromone effects remains unclear. To clarify this point, vomeronasal organ-excising or sham surgeries were performed in male rats for use in 2 experimental models, after which they were exposed to Alarm Pheromone. We found that the vomeronasal organ-excising surgery blocked the effects of this Alarm Pheromone in both the modified open-field test and acoustic startle reflex test. In addition, the results of habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb suggested that the vomeronasal organ-excising surgery completely ablated the vomeronasal organ while preserving the functioning of the main olfactory system. From the above results, we showed that the vomeronasal organ plays an important role in Alarm Pheromone effects in the modified open-field test and acoustic startle reflex test.
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Naloxone blocks the deterioration of male sexual behavior induced by Alarm Pheromone in rats.
Journal of Veterinary Medical Science, 2013Co-Authors: Tatsuya Kobayashi, Sayaka Arata, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Previously, we have demonstrated that the Alarm Pheromone deteriorates sexual behavior in male rats, which was blocked by pretreatment with a corticotrophin-releasing hormone (CRH) antagonist. Studies have shown that an opioid antagonist blocked the deterioration of male sexual behavior following intracerebroventricular administration of CRH. Therefore, possibly, the Pheromone effects could also be mediated by the opioid system. In this study, we pretreated rats with naloxone, an opioid receptor antagonist, and examined the following sexual behavior modulations in male rats that were exposed to the Alarm Pheromone. Naloxone blocked the deterioration of sexual behavior in a dose-dependent manner. On the basis of these data and the results of the previous study, we conclude that the Alarm Pheromone activates the CRH system, which then activates the opioid system, to deteriorate male sexual behavior.
Yukari Takeuchi - One of the best experts on this subject based on the ideXlab platform.
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Alarm Pheromone does not modulate 22-kHz calls in male rats
Physiology & behavior, 2016Co-Authors: Hiromi Muyama, Yasushi Kiyokawa, Yukari Takeuchi, Hideaki Inagaki, Yuji MoriAbstract:Rats are known to emit a series of ultrasonic vocalizations, termed 22-kHz calls, when exposed to distressing stimuli. Pharmacological studies have indicated that anxiety mediates 22-kHz calls in distressed rats. We previously found that exposure to the rat Alarm Pheromone increases anxiety in rats. Therefore, we hypothesized that the Alarm Pheromone would increase 22-kHz calls in Pheromone-exposed rats. Accordingly, we tested whether exposure to the Alarm Pheromone induced 22-kHz calls, as well as whether the Alarm Pheromone increased 22-kHz calls in response to an aversive conditioned stimulus (CS). Rats were first fear-conditioned to an auditory and contextual CS. On the following day, the rats were either exposed to the Alarm Pheromone or a control odor that was released from the neck region of odor-donor rats. Then, the rats were re-exposed to the aversive CS. The Alarm Pheromone neither induced 22-kHz calls nor increased 22-kHz calls in response to the aversive CS. In contrast, the control odor unexpectedly reduced the total number and duration of 22-kHz calls elicited by the aversive CS, as well as the duration of freezing. These results suggest that the Alarm Pheromone does not affect 22-kHz calls in rats. However, we may have found evidence for an appeasing olfactory signal, released from the neck region of odor-donor rats.
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temporary inactivation of the anterior part of the bed nucleus of the stria terminalis blocks Alarm Pheromone induced defensive behavior in rats
Frontiers in Neuroscience, 2015Co-Authors: Tino Breitfeld, Yasushi Kiyokawa, Yukari Takeuchi, Hideaki Inagaki, Johann E A Bruning, Markus FendtAbstract:Rats emit an Alarm Pheromone in threatening situations. Exposure of rats to this Alarm Pheromone induces defensive behaviors, such as head out behavior, and increases c-Fos expression in brain areas involved in the mediation of defensive behaviors. One of these brain areas is the anterior bed nucleus of the stria terminalis (aBNST). The goal of the present study was to investigate if pharmacological inactivation of the aBNST by local microinjections of the GABAA receptor-agonist muscimol modulates Alarm Pheromone-induced defensive behaviors. We first established the behavioral paradigm of Alarm Pheromone-induced defensive behaviors in Sprague-Dawley rats in our laboratory. In a second experiment, we inactivated the aBNST, then exposed rats to one of four different odors (neck odor, female urine, Alarm Pheromone, fox urine) and tested the effects of the aBNST inactivation on the behavior in response to these odors. Our data show that temporary inactivation of the aBNST blocked head out behavior in response to the Alarm Pheromone. This indicates that the aBNST plays an important role in the mediation of the Alarm Pheromone-induced defensive behavior in rats.
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neural correlates underlying naloxone induced amelioration of sexual behavior deterioration due to an Alarm Pheromone
Frontiers in Neuroscience, 2015Co-Authors: Tatsuya Kobayashi, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Sexual behavior is suppressed by various types of stressors. We previously demonstrated that an Alarm Pheromone released by stressed male Wistar rats is a stressor to other rats, increases the number of mounts needed for ejaculation, and decreases the hit rate (described as the number of intromissions/sum of the mounts and intromissions). This deterioration in sexual behavior was ameliorated by pretreatment with the opioid receptor antagonist naloxone. However, the neural mechanism underlying this remains to be elucidated. Here, we examined Fos expression in 31 brain regions of Pheromone-exposed rats and naloxone-pretreated Pheromone-exposed rats 60 min after 10 intromissions. As previously reported, the Alarm Pheromone increased the number of mounts and decreased the hit rate. In addition, Fos expression was increases in the anterior medial division, anterior lateral division and posterior division of the bed nucleus of the stria terminalis, parvocellular part of the paraventricular nucleus of the hypothalamus, arcuate nucleus, dorsolateral and ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Fos expression decreased in the magnocellular part of the paraventricular nucleus of the hypothalamus. Pretreatment with naloxone blocked the Pheromone-induced changes in Fos expression in the magnocellular part of the paraventricular nucleus of the hypothalamus, ventrolateral periaqueductal gray, and nucleus paragigantocellularis. Based on these results, we hypothesize that the Alarm Pheromone deteriorated sexual behavior by activating the ventrolateral periaqueductal gray-nucleus paragigantocellularis cluster and suppressing the magnocellular part of the paraventricular nucleus of the hypothalamus via the opioidergic pathway.
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Alarm Pheromone Is Detected by the Vomeronasal Organ in Male Rats
Chemical senses, 2013Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Yuka Kodama, Takahiro Kubota, Yuji MoriAbstract:It is widely known that a stressed animal releases specific Pheromones, possibly for Alarming nearby conspecifics. We previously investigated an Alarm Pheromone in male rats and found that this Alarm Pheromone evokes several responses, including increases in the defensive and risk assessment behaviors in a modified open-field test, and enhancement of the acoustic startle reflex. However, the role of the vomeronasal organ in these Pheromone effects remains unclear. To clarify this point, vomeronasal organ-excising or sham surgeries were performed in male rats for use in 2 experimental models, after which they were exposed to Alarm Pheromone. We found that the vomeronasal organ-excising surgery blocked the effects of this Alarm Pheromone in both the modified open-field test and acoustic startle reflex test. In addition, the results of habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb suggested that the vomeronasal organ-excising surgery completely ablated the vomeronasal organ while preserving the functioning of the main olfactory system. From the above results, we showed that the vomeronasal organ plays an important role in Alarm Pheromone effects in the modified open-field test and acoustic startle reflex test.
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Naloxone blocks the deterioration of male sexual behavior induced by Alarm Pheromone in rats.
Journal of Veterinary Medical Science, 2013Co-Authors: Tatsuya Kobayashi, Sayaka Arata, Yasushi Kiyokawa, Yukari Takeuchi, Yuji MoriAbstract:Previously, we have demonstrated that the Alarm Pheromone deteriorates sexual behavior in male rats, which was blocked by pretreatment with a corticotrophin-releasing hormone (CRH) antagonist. Studies have shown that an opioid antagonist blocked the deterioration of male sexual behavior following intracerebroventricular administration of CRH. Therefore, possibly, the Pheromone effects could also be mediated by the opioid system. In this study, we pretreated rats with naloxone, an opioid receptor antagonist, and examined the following sexual behavior modulations in male rats that were exposed to the Alarm Pheromone. Naloxone blocked the deterioration of sexual behavior in a dose-dependent manner. On the basis of these data and the results of the previous study, we conclude that the Alarm Pheromone activates the CRH system, which then activates the opioid system, to deteriorate male sexual behavior.
Henry Fadamiro - One of the best experts on this subject based on the ideXlab platform.
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intra and inter specific variation in Alarm Pheromone produced by solenopsis fire ants
Bulletin of Entomological Research, 2017Co-Authors: Rammohan R Balusu, Henry Fadamiro, W Q Zhang, Olufemi S Ajayi, Rensen Zeng, Li Zi-chenAbstract:Some fire ants of the genus Solenopsis have become invasive species in the southern United States displacing native species by competition. Although the displacement pattern seems clear, the mechanisms underlying competitive advantage remain unclear. The ability of ant workers to produce relatively larger amount of Alarm Pheromone may correspond to relative greater fitness among sympatric fire ant species. Here we report on quantitative intra-specific (i.e. inter-caste) and inter-specific differences of Alarm Pheromone component, 2-ethyl-3,6-dimethylpyrazine (2E36DMP), for several fire ant species. The Alarm Pheromone component was extracted by soaking ants in hexane for 48 h and subsequently quantified by gas chromatography-mass spectrometry at single ion monitoring mode. Solenopsis invicta workers had more 2E36DMP than male or female alates by relative weight; individual workers, however, contained significantly less pyrazine. We thus believe that Alarm Pheromones may serve additional roles in alates. Workers of Solenopsis richteri, S. invicta, and hybrid (S. richteri × S. invicta) had significantly more 2E36DMP than a native fire ant species, Solenopsis geminata. The hybrid fire ant had significantly less 2E36DMP than the two parent species, S. richteri and S. invicta. It seems likely that higher Alarm Pheromone content may have favored invasion success of exotic fire ants over native species. We discuss the potential role of inter-specific variation in pyrazine content for the relationship between the observed shifts in the spatial distributions of the three exotic fire ant species in southern United States and the displacement of native fire ant species.
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Comparative responses of four Pseudacteon phorid fly species to host fire ant Alarm Pheromone and analogs
Chemoecology, 2015Co-Authors: Esther Ngumbi, Henry FadamiroAbstract:Several species of Pseudacteon phorid flies, including Pseudacteon cultellatus , P. curvatus , P. obtusus , and P. tricuspis , have been introduced in the southern United States for biological control of imported fire ants, Solenopsis spp. Previous studies showed that Pseudacteon flies use the Alarm Pheromone and venom alkaloids of fire ants to locate host ant workers. A recent study by our group demonstrated attraction of one of the species, P. tricuspis , to certain alkylpyrazine analogs of fire ant Alarm Pheromone. If effective, alkylpyrazine analogs of fire ant Alarm Pheromone may provide cost-efficient alternatives as phorid fly attractants. To test the hypothesis that other phorid fly species are attracted to alkylpyrazine analogs of fire ant Alarm Pheromone, we compared electroantennogram (EAG) and behavioral responses of four Pseudacteon species, P. cultellatus , P. curvatus , P. obtusus , and P. tricuspis , to the commercially available Alarm Pheromone isomer (2-ethyl-3,6(or 5)-dimethyl pyrazine) and six structurally related alkylpyrazine analogs at physiologically relevant doses (ranging from picogram to 10 µg). The Alarm Pheromone isomer and two analogs, 2,3-diethyl-5-methyl pyrazine and 2 ethyl-3,5 + 6 methyl pyrazine, elicited the strongest EAG activity in all four species at all tested doses. Results from four-choice olfactometer bioassays testing the above three EAG-active compounds showed that all four species were strongly attracted to the Alarm Pheromone isomer at doses ranging from 0.001 to 1 µg. The flies also showed significant attraction to the two analogs (2,3-diethyl-5-methyl pyrazine and 2 ethyl-3,5 + 6 methyl pyrazine) compared to the solvent control but not as strong as the attraction elicited by the Alarm Pheromone isomer. These results confirm that multiple species of phorid flies use fire ant Alarm Pheromone as a host location cue. However, the flies are not strongly attracted to the tested alkylpyrazine analogs of the Alarm Pheromone.
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fire ant Alarm Pheromone and venom alkaloids act in concert to attract parasitic phorid flies pseudacteon spp
Journal of Insect Physiology, 2013Co-Authors: Kavita R Sharma, Henry FadamiroAbstract:Pseudacteon tricuspis, Pseudacteon obtusus and Pseudacteon curvatus are three species of parasitic phorid flies (Diptera: Phoridae), which have been introduced as classical biological control agents of imported, Solenopsis fire ants (Hymenoptera: Formicidae) in the southern USA. Previous studies demonstrated the behavioral response of P. tricuspis to the venom alkaloids and Alarm Pheromone of the fire ant, S. invicta. In the present study, we compared the responses of P. tricuspis, P. obtusus and P. curvatus to Solenopsis invicta Alarm Pheromone, venom alkaloids, or a mixture of both chemicals in four-choice olfactometer bioassays. The main hypothesis tested was that the fire ant Alarm Pheromone and venom alkaloids act in concert to attract Pseudacteon phorid flies. Both sexes of all three Pseudacteon species were attracted to low doses of the fire ant Alarm Pheromone or venom alkaloids (i.e. 1 ant worker equivalent) alone. However, the flies were significantly more attracted to a mixture of both chemicals (i.e., 1:1 mixture of Alarm Pheromone + alkaloids) than to either chemical. The results suggest an additive rather than a synergistic effect of combining both chemicals. Comparing the fly species, P. tricuspis showed relatively greater attraction to cis alkaloids, whereas the alkaloid mixture (cis + trans) was preferred by P. obtusus and P. curvatus. In general, no key sexual differences were recorded, although females of P. tricuspis and P. obtusus showed slightly higher response than conspecific males to lower doses of the Alarm Pheromone. The ecological significance of these findings is discussed, and a host location model is proposed for parasitic phorid flies involving the use of fire ant Alarm Pheromone and venom alkaloids as long range and short range attractants, respectively.
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phorid fly pseudacteon tricuspis response to alkylpyrazine analogs of a fire ant solenopsis invicta Alarm Pheromone
Journal of Insect Physiology, 2011Co-Authors: Kavita R Sharma, Robert Vander K Meer, Henry FadamiroAbstract:Abstract The phorid fly, Pseudacteon tricuspis Borgmeier, is a parasitoid of the red imported fire ant, Solenopsis invicta Buren. This fly has been reported to use fire ant chemicals, specifically venom alkaloids and possibly Alarm Pheromone to locate its host. A recent study identified 2-ethyl-3,6-dimethyl pyrazine as a component of the Alarm Pheromone of S. invicta. To determine the possible involvement of this fire ant Alarm Pheromone component in mediating fire ant-phorid fly interactions, we tested electroantennogram (EAG) and behavioral responses of P. tricuspis females to the commercially available mixture of 2-ethyl-3,6-dimethyl pyrazine and its 3,5-dimethyl isomer, as well as six structurally related alkylpyrazine analogs at varying doses. Pseudacteon tricuspis females showed significant EAG response to 2-ethyl-3,6(or 5)-dimethyl pyrazine (herein referred to as Pheromone-isomer) at all doses, 0.001–10 μg. Among the tested alkylpyrazine analogs, 2,3-diethyl-5-methyl pyrazine showed significant EAG activity at 0.1 and 1 μg. 2,3-dimethyl pyrazine also showed significant EAG activity at 0.1 μg. Results of four-choice olfactometer bioassays demonstrated significant attraction of P. tricuspis females to the Pheromone-isomer (2-ethyl-3,6(or 5)-dimethyl pyrazine) at all tested doses (0.01, 0.1, 1 and 10 μg). The analogs, 2,3-diethyl-5-methyl pyrazine and 2,3-dimethyl pyrazine were significantly better than the control at the higher doses (0.1, 1 and 10 μg). The Pheromone-isomer was significantly better than both analogs at two doses, 0.1 and 1 μg. These results confirm that the reported fire ant Alarm Pheromone component plays a role in mediating attraction of phorid flies to host workers. Venom alkaloids were previously shown to attract P. tricuspis ; therefore, we propose that fire ant Alarm Pheromones may act in tandem or synergistically with venom alkaloids to attract phorid fly parasitoids to fire ant workers.
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phorid fly pseudacteon tricuspis response to alkylpyrazine analogs of a fire ant solenopsis invicta Alarm Pheromone
Journal of Insect Physiology, 2011Co-Authors: Kavita R Sharma, Robert Vander K Meer, Henry FadamiroAbstract:Abstract The phorid fly, Pseudacteon tricuspis Borgmeier, is a parasitoid of the red imported fire ant, Solenopsis invicta Buren. This fly has been reported to use fire ant chemicals, specifically venom alkaloids and possibly Alarm Pheromone to locate its host. A recent study identified 2-ethyl-3,6-dimethyl pyrazine as a component of the Alarm Pheromone of S. invicta. To determine the possible involvement of this fire ant Alarm Pheromone component in mediating fire ant-phorid fly interactions, we tested electroantennogram (EAG) and behavioral responses of P. tricuspis females to the commercially available mixture of 2-ethyl-3,6-dimethyl pyrazine and its 3,5-dimethyl isomer, as well as six structurally related alkylpyrazine analogs at varying doses. Pseudacteon tricuspis females showed significant EAG response to 2-ethyl-3,6(or 5)-dimethyl pyrazine (herein referred to as Pheromone-isomer) at all doses, 0.001–10 μg. Among the tested alkylpyrazine analogs, 2,3-diethyl-5-methyl pyrazine showed significant EAG activity at 0.1 and 1 μg. 2,3-dimethyl pyrazine also showed significant EAG activity at 0.1 μg. Results of four-choice olfactometer bioassays demonstrated significant attraction of P. tricuspis females to the Pheromone-isomer (2-ethyl-3,6(or 5)-dimethyl pyrazine) at all tested doses (0.01, 0.1, 1 and 10 μg). The analogs, 2,3-diethyl-5-methyl pyrazine and 2,3-dimethyl pyrazine were significantly better than the control at the higher doses (0.1, 1 and 10 μg). The Pheromone-isomer was significantly better than both analogs at two doses, 0.1 and 1 μg. These results confirm that the reported fire ant Alarm Pheromone component plays a role in mediating attraction of phorid flies to host workers. Venom alkaloids were previously shown to attract P. tricuspis ; therefore, we propose that fire ant Alarm Pheromones may act in tandem or synergistically with venom alkaloids to attract phorid fly parasitoids to fire ant workers.
Takefumi Kikusui - One of the best experts on this subject based on the ideXlab platform.
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The volatility of an Alarm Pheromone in male rats.
Physiology & behavior, 2008Co-Authors: Hideaki Inagaki, Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Kayo Nakamura, Yuji MoriAbstract:The volatility of an Alarm Pheromone in male rats. PHYSIOL BEHAV 00(0) 000-000, 2008. We previously reported that an Alarm Pheromone released from the perianal region of male rats is perceived by the vomeronasal organ and evokes stress-induced hyperthermia and defensive and risk assessment behavior. In addition, we recently reported that the Alarm Pheromone enhances the acoustic startle reflex (ASR). However, in contrast to our knowledge about such biological aspects of the Pheromone, information concerning the physical character of the Alarm Pheromone is extremely limited. In this study, we investigated the volatility of the Alarm Pheromone using enhancement of the ASR as an index of the Pheromone effect. The Alarm Pheromone enhanced the ASR when it was presented at a distance of 10 mm but not at 200 mm. In addition, the Pheromone effect was observed even after the Pheromone was trapped in the adsorbent (Tenax) and then extracted using purified water. These results suggest that the Alarm Pheromone is both volatile and water soluble.
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Enhancement of the acoustic startle reflex by an Alarm Pheromone in male rats.
Physiology & behavior, 2007Co-Authors: Hideaki Inagaki, Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Yuji MoriAbstract:Recently, we reported that an Alarm Pheromone released from the perianal region of male rats aggravated stress-induced hyperthermia and increased defensive and risk assessment behaviors in recipient male rats. Based on these results, we hypothesized that the primary effect of the Alarm Pheromone is to increase anxiety; however, there is still no clear evidence for this Pheromone effect. Therefore, we examined this issue by assessing the effect of the Alarm Pheromone on the acoustic startle reflex (ASR), which is a useful index for studying negative emotions such as anxiety in rats. The Alarm Pheromone enhanced the ASR for 105-dB auditory stimuli, but not for those of 90 and 120 dB, when these three intensities of sound were used randomly. The same results were obtained when one of these three intensities was used repeatedly. In addition, pretreatment with diazepam (i.p.) at doses of 0.7 and 2.0 mg/kg suppressed the ASR of the Pheromone recipients, whereas the lower dose (0.2 mg/kg) slightly attenuated the Pheromone effect and the control injection (vehicle) had no effect. These results indicate that the Alarm Pheromone enhances the ASR by increasing anxiety in recipient rats, suggesting that the primary effect of the Alarm Pheromone is to increase the anxiety level.
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Removal of the Vomeronasal Organ Blocks the Stress-Induced Hyperthermia Response to Alarm Pheromone in Male Rats
Chemical senses, 2006Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Yuji MoriAbstract:Previously, we reported that male Wistar rats release Alarm Pheromone from their perianal region, which aggravates stressinduced hyperthermia (SIH) in Pheromone-recipient rats. The subsequent discovery that this Pheromone could be trapped in water enabled us to expose recipients to the Pheromone in their home cages. Despite its apparent influence on autonomic and behavioral functions, we still had no clear evidence as to whether the Alarm Pheromone was perceived by the main olfactory system (MOS) or by the vomeronasal system. In this study, we investigated this question by exposing 3 types of recipients to Alarm Pheromone in their home cages: intact males (Intact), vomeronasal organ–excised males (VNX), and sham-operated males (Sham). The Intact and Sham recipients showed aggravated SIH in response to Alarm Pheromone, whereas the VNX recipients did not. In addition, the results of the habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb verified the complete ablation of the vomeronasal organ (VNO) with a functional MOS in the Pheromone recipients. These results strongly suggest that male rats perceive Alarm Pheromone with the VNO.
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Alarm Pheromone increases defensive and risk assessment behaviors in male rats.
Physiology & behavior, 2005Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Michito Shimozuru, Yuji MoriAbstract:Abstract Previously, we reported that Alarm Pheromone released from the perianal region of male rats aggravated stress-induced hyperthermia and increased Fos expression in the vomeronasal pathway and stress-related nuclei in Pheromone-recipient rats. However, the Alarm property of this Pheromone in terms of behavior modification is still unclear. We recently found that this Alarm Pheromone could be trapped in water. Based on this finding, we developed an experimental paradigm to assess the effect of Alarm Pheromone on recipient behavior. Male Wistar rats were acclimatized for 5 min to an open field, where two pieces of filter paper soaked with 750 μl of either Pheromone-containing water or vehicle water were attached to the wall. Then, a small “hiding box” was placed in one corner of the field and the behavioral responses of the subject rat were recorded for 10 subsequent minutes. Exposure to Alarm Pheromone significantly increased defensive and risk assessment behaviors and decreased exploratory and grooming behaviors compared to the vehicle control group, indicating the Alarm property of the Pheromone. In addition, the comparison with previous results suggests that the Alarm Pheromone released from the perianal region of the male rat increases anxiety in recipients, rather than evoking a stereotyped autonomic response.
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Alarm Pheromone that Aggravates Stress-induced Hyperthermia is Soluble in Water
Chemical senses, 2005Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Yuji MoriAbstract:We previously reported that stressed male Wistar rats released Alarm Pheromone from the perianal region, which aggravated stress-induced hyperthermia and increased Fos expression in the mitral/tufted cell layer of the accessory olfactory bulb in recipient rats. In this study, we attempted to obtain this Pheromone in water using these responses as bioassay parameters. Water droplets were collected from the ceiling of a box in which no animal was placed, or from a box in which an anesthetized donor rat was given electrical stimulation to either the neck or perianal regions in order to induce neck odor or Alarm Pheromone release, respectively. Then we placed one of the three kinds of water-containing filter papers on the wall of a recipient’s home cage and observed heart rate, body temperature and behavioral responses, as well as Fos expression in the main and accessory olfactory bulbs of the recipient. The water collected from the box containing the Alarm Pheromone was found to generate a reproduction of all of the responses seen in the animal that had been directly exposed to Alarm Pheromone in our previous studies. These results suggest that the Alarm Pheromone is soluble in water.
