Changes in single-unit activity in the ventromedial hypothalamic nucleus of goats during feeding |
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| Authors: | Itsuki NAGAMINE Katsunori SUNAGAWA Akihisa SHINJO |
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| Institution: | Faculty of Agriculture, University of the Ryukyus, Nishihara-cho, Okinawa-ken, Japan |
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| Abstract: | In this study we used a single‐unit activity (SUA) recording electrode to investigate the existence of appetite‐regulating neurons in the ventromedial hypothalamic nucleus (VMH) in goats. Five male Japanese Saanen goats were used. The animals were fed at 10.00 hours with alfalfa hay cubes, and at 16.00 hours with concentrate feed and hay. The animals were allowed free access to drinking water. The present experiment consisted of two treatments, non‐infusion (NI) and an intra‐ruminal water infusion (RWI). The SUA recordings were carried out continuously over a 130 min period beginning 10 min prior to the commencement of morning feeding. In the RWI treatment, warm water was infused intra‐ruminally before the SUA recording. Eating rates in the NI treatment decreased sharply by the time 40 min had elapsed and then remained at low levels. In the RWI treatment, eating rates decreased by the time 50 min had elapsed and then remained at low levels. This study recorded 19 units, of which four units increased their firing rates when the animals became satiated (i.e. when eating rates declined to low levels) in both treatments. The four units were located in the VMH. The results suggest that cells located in the VMH of goats are active in the control of hay intake. |
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| Keywords: | feeding behavior goats intra-ruminal water infusion single-unit activity ventromedial hypothalamic nucleus |
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