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Kazumasa Honda - One of the best experts on this subject based on the ideXlab platform.
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effects of unilateral electrolytic lesion of the dorsomedial nucleus of the hypothalamus on milk ejection reflex in the rat
Journal of Reproduction and Development, 2010Co-Authors: Kazumasa Honda, Takashi HiguchiAbstract:The dorsomedial nucleus of the hypothalamus (DMH) has been suggested to be a final relay site for the afferent pathway of milk-ejection reflex (MER). The present experiments were undertaken to examine whether unilateral lesion of the DMH abolished MER induced by unilateral Suckling by pups. The unilateral DMHs of urethane-anesthetized lactating rats were electrolytically lesioned. Then 5 pups were applied to nipples ipsilateral or contralateral to the lesioned DMH and the intramammary pressure was monitored to observe the occurrence of MER. The effects of bilateral Suckling by 10 pups were also examined. Eighteen of the 29 rats displayed MER during ipsi- or bilateral Suckling for about 1 h. Seventeen of these 18 rats did not show MER during contralateral Suckling for about 1 h. The remaining rat that showed milk ejection during contralateral Suckling had a lesion outside the DMH. In 2 additional rats, extracellular action potentials of single oxytocin (OT) cells located in the supraoptic nucleus ipsilateral to the lesioned DMH were recorded during Suckling ipsi- and conralateral to the lesioned DMH. OT cells showed milk-ejection burst during ipsilateral Suckling but not during contralateral Suckling. The results suggest that the unilateral DMH receives information of Suckling stimuli applied to contralateral nipples.
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milk ejection bursts of supraoptic oxytocin neurones during bilateral and unilateral Suckling in the rat
Journal of Neuroendocrinology, 1996Co-Authors: Yufeng Wang, H Negoro, Kazumasa HondaAbstract:Extracellular recordings of the electrical activity of oxytocin neurones were made from the supraoptic nuclei (SON) of lactating rats, and the milk-ejection bursts and the background activity of oxytocin neurones were investigated during unilateral and bilateral Suckling. When application of pups was limited to the nipples on either the same side (ipsilateral Suckling) or the side opposite (contralateral Suckling) to the oxytocin neurone recorded, the burst amplitude and background firing rate were significantly (P < 0.05) lower and the inter-burst interval was significantly (P < 0.05) longer than during bilateral Suckling. Furthermore, the burst amplitude was significantly (P < 0.05) lower during ipsilateral Suckling than during contralateral Suckling. The majority of the oxytocin neurones showed a gradual increase in the burst amplitude during bilateral (88.9%) and contralateral (77.3%) Suckling, but during ipsilateral Suckling only 40% of the neurones did. The inter-burst interval became shorter with the progress of the milk ejection reflex during any mode of Suckling. Three pairs of oxytocin neurones recorded simultaneously from both SON were successfully tested for the effect of bilateral and unilateral Suckling on the electrical activity, and the results showed the same direction of change in the burst amplitude, background activity and burst interval as shown in single side recordings. These findings indicate that the burst amplitude mainly depends on the amount of afferent Suckling signals arising from the nipples on the side opposite to the recording side, and that there may exist bilateral summation centres coordinating with the synchronization mechanism of milk-ejection bursts of oxytocin neurones.
K Honda - One of the best experts on this subject based on the ideXlab platform.
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effects of hemitransection of the midbrain on milk ejection burst of oxytocin neurones in lactating rat
Journal of Endocrinology, 1995Co-Authors: Y F Wang, H Negoro, K HondaAbstract:Unilateral knife cuts were performed in the midbrain of lactating rats and the activities of oxytocin neurones were recorded extracellularly from the supraoptic nuclei (SON) in order to investigate the location of the neural mechanism responsible for the synchronization of milk-ejection bursts of oxytocin neurones in different magnocellular nuclei of the hypothalamus. The lesions involved the mesencephalic lateral tegmentum, the intermedial tegmentum and the central grey. Ninety-six SON neurones were antidromically activated by neurohypophyseal stimulation and were also identified as oxytocin neurones, which included 17 pair-recorded neurones. First, the response of oxytocin neurones recorded from the unilateral SON to bilateral or unilateral Suckling was tested. During bilateral Suckling, not only the oxytocin neurones recorded from the SON on the intact side (n=34) but also those recorded from the SON on the lesioned side (n=58) displayed min-ejection bursts. When only the nipples ipsilateral to the lesion were sucked (ipsilateral Suckling), bursts were induced in most of the oxytocin neurones on the intact (83.3%, n=12) and lesioned side (88.9%, n=27). In contrast, none of the oxytocin neurones (n=37) produced bursts and none of the rats tested (n=23) showed milk ejections during contralateral Suckling. Secondly, some characteristics of the bursts of pair-recorded neurones during bilateral Suckling and their response to different modes of Suckling were investigated. When oxytocin neurones on both sides displayed milk-ejection bursts, they were always well synchroized but the mean burst amplitude of the neurones on the lesioned side (55.6±4.9spines, n=43) was significantly (P<0.05) lower than that of the neurones on the intact side (65.7±5.6 spines, n=43). Late-recruited neurones were observed in 6 pairs of oxytocin neurones, and these mainly occurred in the neurones on the lesioned side (5/6). In 5 pair-recorded oxytocin neurones, bursts could also be induced synchronously by ipsilateral Suckling but not by contralateral Suckling. Thus it is very likely that the major mechanism synchronizing the milk-ejection bursts of oxytocin neurones in the bilateral SON is located in the region rostral to the midbrain
H Negoro - One of the best experts on this subject based on the ideXlab platform.
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milk ejection bursts of supraoptic oxytocin neurones during bilateral and unilateral Suckling in the rat
Journal of Neuroendocrinology, 1996Co-Authors: Yufeng Wang, H Negoro, Kazumasa HondaAbstract:Extracellular recordings of the electrical activity of oxytocin neurones were made from the supraoptic nuclei (SON) of lactating rats, and the milk-ejection bursts and the background activity of oxytocin neurones were investigated during unilateral and bilateral Suckling. When application of pups was limited to the nipples on either the same side (ipsilateral Suckling) or the side opposite (contralateral Suckling) to the oxytocin neurone recorded, the burst amplitude and background firing rate were significantly (P < 0.05) lower and the inter-burst interval was significantly (P < 0.05) longer than during bilateral Suckling. Furthermore, the burst amplitude was significantly (P < 0.05) lower during ipsilateral Suckling than during contralateral Suckling. The majority of the oxytocin neurones showed a gradual increase in the burst amplitude during bilateral (88.9%) and contralateral (77.3%) Suckling, but during ipsilateral Suckling only 40% of the neurones did. The inter-burst interval became shorter with the progress of the milk ejection reflex during any mode of Suckling. Three pairs of oxytocin neurones recorded simultaneously from both SON were successfully tested for the effect of bilateral and unilateral Suckling on the electrical activity, and the results showed the same direction of change in the burst amplitude, background activity and burst interval as shown in single side recordings. These findings indicate that the burst amplitude mainly depends on the amount of afferent Suckling signals arising from the nipples on the side opposite to the recording side, and that there may exist bilateral summation centres coordinating with the synchronization mechanism of milk-ejection bursts of oxytocin neurones.
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effects of hemitransection of the midbrain on milk ejection burst of oxytocin neurones in lactating rat
Journal of Endocrinology, 1995Co-Authors: Y F Wang, H Negoro, K HondaAbstract:Unilateral knife cuts were performed in the midbrain of lactating rats and the activities of oxytocin neurones were recorded extracellularly from the supraoptic nuclei (SON) in order to investigate the location of the neural mechanism responsible for the synchronization of milk-ejection bursts of oxytocin neurones in different magnocellular nuclei of the hypothalamus. The lesions involved the mesencephalic lateral tegmentum, the intermedial tegmentum and the central grey. Ninety-six SON neurones were antidromically activated by neurohypophyseal stimulation and were also identified as oxytocin neurones, which included 17 pair-recorded neurones. First, the response of oxytocin neurones recorded from the unilateral SON to bilateral or unilateral Suckling was tested. During bilateral Suckling, not only the oxytocin neurones recorded from the SON on the intact side (n=34) but also those recorded from the SON on the lesioned side (n=58) displayed min-ejection bursts. When only the nipples ipsilateral to the lesion were sucked (ipsilateral Suckling), bursts were induced in most of the oxytocin neurones on the intact (83.3%, n=12) and lesioned side (88.9%, n=27). In contrast, none of the oxytocin neurones (n=37) produced bursts and none of the rats tested (n=23) showed milk ejections during contralateral Suckling. Secondly, some characteristics of the bursts of pair-recorded neurones during bilateral Suckling and their response to different modes of Suckling were investigated. When oxytocin neurones on both sides displayed milk-ejection bursts, they were always well synchroized but the mean burst amplitude of the neurones on the lesioned side (55.6±4.9spines, n=43) was significantly (P<0.05) lower than that of the neurones on the intact side (65.7±5.6 spines, n=43). Late-recruited neurones were observed in 6 pairs of oxytocin neurones, and these mainly occurred in the neurones on the lesioned side (5/6). In 5 pair-recorded oxytocin neurones, bursts could also be induced synchronously by ipsilateral Suckling but not by contralateral Suckling. Thus it is very likely that the major mechanism synchronizing the milk-ejection bursts of oxytocin neurones in the bilateral SON is located in the region rostral to the midbrain
K Svennerstensjaunja - One of the best experts on this subject based on the ideXlab platform.
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effect of Suckling on the release of oxytocin prolactin cortisol gastrin cholecystokinin somatostatin and insulin in dairy cows and their calves
Journal of Dairy Research, 2001Co-Authors: Berit Lupoli, Birgitta Johansson, Kerstin Uvnasmoberg, K SvennerstensjaunjaAbstract:The aim of the present study was to examine how different types of early interaction between dairy cows and their calves influence milking/Suckling-related hormone release in the cows and sucking/bucket-drinking related hormone release in calves. Eighteen cows of the Swedish Red and White breed were studied during the first week after parturition. The cows were machine milked twice daily, and allotted to one of three treatments: [1] cow and calf were kept together and the cow was allowed to suckle the calf for 30 min about 1 h before each milking: [2] cow and calf were kept together and the calf was bucket fed twice daily: and [3] cow and calf were separated immediately after parturition, and the calf was kept in a single box and was bucket fed twice daily. Blood samples were collected around day 7 from both cows and calves. The plasma levels of oxytocin, prolactin, cortisol, gastrin. cholecystokinin (CCK). somatostatin and insulin were analysed. In the cows the levels of oxytocin, prolactin and cortisol were influenced by all three treatments. except for the level of cortisol which did not respond to Suckling. The main finding was that the release of oxytocin was significantly greater during Suckling compared with machine milking. In the calves, the hormone levels were also influenced by the different milk feeding routines. The plasma concentrations of oxytocin, gastrin. CCK and insulin increased in response to milk ingestion in all treatments. However, during sucking, the increase of oxytocin was significantly greater than during bucket drinking. In addition, a strong correlation between oxytocin and insulin was found in response to sucking. Further, significant inereases in prolactin and somatostatin. and a decrease in cortisol were found during sucking. The level of somatostatin also increased in response to bucket feeding when calves were kept separately. During bucket feeding, no significant correlation was found with oxytocin, but strong correlations between the gastrointestinal hormones gastrin. CCK, somatostatin and insulin were seen. Together these data suggest that different hormonal patterns were triggered in the cows by Suckling and milking, and in the calves by sucking and bucket drinking. This is further supported by different correlation patterns observed in the calves in response to sucking and bucket feeding. The present findings imply that management routines for cows and calves during the first week after parturition have consequences for the physiology of the animals.
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effect of Suckling on the release of oxytocin prolactin cortisol gastrin cholecystokinin somatostatin and insulin in dairy cows and their calves
Journal of Dairy Research, 2001Co-Authors: Berit Lupoli, Birgitta Johansson, Kerstin Uvnasmoberg, K SvennerstensjaunjaAbstract:The aim of the present study was to examine how different types of early interaction between dairy cows and their calves influence milking/Suckling-related hormone release in the cows and sucking/bucket-drinking related hormone release in calves. Eighteen cows of the Swedish Red and White breed were studied during the first week after parturition. The cows were machine milked twice daily, and allotted to one of three treatments: [1] cow and calf were kept together and the cow was allowed to suckle the calf for 30 min about 1 h before each milking; [2] cow and calf were kept together and the calf was bucket fed twice daily; and [3] cow and calf were separated immediately after parturition, and the calf was kept in a single box and was bucket fed twice daily. Blood samples were collected around day 7 from both cows and calves. The plasma levels of oxytocin, prolactin, cortisol, gastrin, cholecystokinin (CCK), somatostatin and insulin were analysed. In the cows the levels of oxytocin, prolactin and cortisol were influenced by all three treatments, except for the level of cortisol which did not respond to Suckling. The main finding was that the release of oxytocin was as significantly greater during Suckling compared with machine milking. In the calves, the hormone levels were also influenced by the different milk feeding routines. The plasma concentrations of oxytocin, gastrin, CCK and insulin increased in response to milk ingestion in all treatments. However, during sucking, the increase of oxytocin was significantly greater than during bucket drinking. In addition, a strong correlation between oxytocin and insulin was found in response to sucking. Further, significant increases in prolactin and somatostatin, and a decrease in cortisol were found during sucking. The level of somatostatin also increased in response to bucket feeding when calves were kept separately. During bucket feeding, no significant correlation was found with oxytocin, but strong correlations between the gastrointestinal hormones gastrin, CCK, somatostatin and insulin were seen. Together these data suggest that different hormonal patterns were triggered in the cows by Suckling and milking and in the calves by sucking and bucket drinking. This is further supported by different correlation patterns observed in the calves in response to sucking and bucket feeding. The present findings imply that management routines for cows and calves during the first week after parturition have consequences for the physiology of the animals.
Y F Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of hemitransection of the midbrain on milk ejection burst of oxytocin neurones in lactating rat
Journal of Endocrinology, 1995Co-Authors: Y F Wang, H Negoro, K HondaAbstract:Unilateral knife cuts were performed in the midbrain of lactating rats and the activities of oxytocin neurones were recorded extracellularly from the supraoptic nuclei (SON) in order to investigate the location of the neural mechanism responsible for the synchronization of milk-ejection bursts of oxytocin neurones in different magnocellular nuclei of the hypothalamus. The lesions involved the mesencephalic lateral tegmentum, the intermedial tegmentum and the central grey. Ninety-six SON neurones were antidromically activated by neurohypophyseal stimulation and were also identified as oxytocin neurones, which included 17 pair-recorded neurones. First, the response of oxytocin neurones recorded from the unilateral SON to bilateral or unilateral Suckling was tested. During bilateral Suckling, not only the oxytocin neurones recorded from the SON on the intact side (n=34) but also those recorded from the SON on the lesioned side (n=58) displayed min-ejection bursts. When only the nipples ipsilateral to the lesion were sucked (ipsilateral Suckling), bursts were induced in most of the oxytocin neurones on the intact (83.3%, n=12) and lesioned side (88.9%, n=27). In contrast, none of the oxytocin neurones (n=37) produced bursts and none of the rats tested (n=23) showed milk ejections during contralateral Suckling. Secondly, some characteristics of the bursts of pair-recorded neurones during bilateral Suckling and their response to different modes of Suckling were investigated. When oxytocin neurones on both sides displayed milk-ejection bursts, they were always well synchroized but the mean burst amplitude of the neurones on the lesioned side (55.6±4.9spines, n=43) was significantly (P<0.05) lower than that of the neurones on the intact side (65.7±5.6 spines, n=43). Late-recruited neurones were observed in 6 pairs of oxytocin neurones, and these mainly occurred in the neurones on the lesioned side (5/6). In 5 pair-recorded oxytocin neurones, bursts could also be induced synchronously by ipsilateral Suckling but not by contralateral Suckling. Thus it is very likely that the major mechanism synchronizing the milk-ejection bursts of oxytocin neurones in the bilateral SON is located in the region rostral to the midbrain
