Background L-glutamate （L-GLU） is a major neurotransmitter in the nucleus ambiguus （NA）, which can modulate respiration, arterial pressure, heart rate, etc. This study investigated the effects and mechanisms of L-...Background L-glutamate （L-GLU） is a major neurotransmitter in the nucleus ambiguus （NA）, which can modulate respiration, arterial pressure, heart rate, etc. This study investigated the effects and mechanisms of L-GLU microinjected into NA on gastric motility in rats. Methods A latex balloon connected with a pressure transducer was inserted into the pylorus through the forestomach for continuous recording of the gastric motility. The total amplitude, total duration, and motility index of gastric contraction waves within 5 minutes before microinjection and after microinjection were measured. Results L-GLU （5 nmol, 10 nmol and 20 nmol in 50 nl normal saline （PS） respectively） microinjected into the right NA significantly inhibited gastric motility, while microinjection of physiological saline at the same position and the same volume did not change the gastric motility. The inhibitory effect was blocked by D-2-amino-5-phophonovalerate （D-AP5, 5 nmol, in 50 nl PS）, the specific N-methyI-D-aspartic acid （NMDA） receptor antagonist, but was not influenced by 6-cyaon-7-nitroquinoxaline-2,3-（1H,4H）-dione （CNQX） （5 nmol, in 50 nl PS）, the non-NMDA ionotropic receptor antagonist. Bilateral subdiaphragmatic vagotomy abolished the inhibitory effect by microinjection of L-GLU into NA. Conclusions Microinjection of L-GLU into NA inhibits the gastric motility through specific NMDA receptor activity, not non-NMDA receptor activity, and the efferent pathway is the vagal nerves.展开更多
Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of L-leucine, L-glutamate, L-t...Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of L-leucine, L-glutamate, L-tryptophan and L-arginine on feed intake and the mRNA expression levels of hypothalamic Neuropeptide involved in feed intake regulation in broiler chicks. Leucine, glutamate, tryptophan or arginine was intra-cerebroventricularly （ICV） administrated to 4d-old broiler chicks respectively and the feed intake were recorded at various time points. Quantitative PCR was performed to determine the hypothalamic mRNA expression levels of Neuropeptide Y （NPY）, agouti related protein （AgRP）, pro-opiomelanocortin （POMC）, melanocortin receptor 4 （MC4R） and corticotrophin releasing factor （CRF）. Our results showed that ICV administration of L-leucine （0.15 or 1.5 μmol） significantly （P〈0.05） increased feed intake up to 2 h post-administration period and elevated both hypothalamic NPY and AgRP mRNA expression levels. In contrast, ICV administration of L-glutamate （1.6 μmol） significantly （P 〈 0.05） decreased feed intake 0.25, 0.5 and 2 h post-injection, and increased hypothalamic CRF and MC4R mRNA expression levels. Meanwhile, both L-tryptophan （10 or 100 μg） and L-arginine （20 or 200 μg） had no significant effect on feed intake. These findings suggested that L-leucine and L-glutamate could act within the hypothalamus to influence food intake, and that both orexigenic and anorexigenic Neuropeptide genes might contribute directly to these effects.展开更多
基金This study was supported by the grants from the National Natural Science Foundation of China （No. 30770277 and No. 30970354）.
文摘Background L-glutamate （L-GLU） is a major neurotransmitter in the nucleus ambiguus （NA）, which can modulate respiration, arterial pressure, heart rate, etc. This study investigated the effects and mechanisms of L-GLU microinjected into NA on gastric motility in rats. Methods A latex balloon connected with a pressure transducer was inserted into the pylorus through the forestomach for continuous recording of the gastric motility. The total amplitude, total duration, and motility index of gastric contraction waves within 5 minutes before microinjection and after microinjection were measured. Results L-GLU （5 nmol, 10 nmol and 20 nmol in 50 nl normal saline （PS） respectively） microinjected into the right NA significantly inhibited gastric motility, while microinjection of physiological saline at the same position and the same volume did not change the gastric motility. The inhibitory effect was blocked by D-2-amino-5-phophonovalerate （D-AP5, 5 nmol, in 50 nl PS）, the specific N-methyI-D-aspartic acid （NMDA） receptor antagonist, but was not influenced by 6-cyaon-7-nitroquinoxaline-2,3-（1H,4H）-dione （CNQX） （5 nmol, in 50 nl PS）, the non-NMDA ionotropic receptor antagonist. Bilateral subdiaphragmatic vagotomy abolished the inhibitory effect by microinjection of L-GLU into NA. Conclusions Microinjection of L-GLU into NA inhibits the gastric motility through specific NMDA receptor activity, not non-NMDA receptor activity, and the efferent pathway is the vagal nerves.
基金supported by National Key Project(2009CB941601)the Joint Funds of the National Natural Science Foundation of China(u0731004)+3 种基金National Natural Science Foundation of China(30871845,30901058 and 30972157)the Natural Science Foundation of Guangdong Province of China(9451064201003790 and 9151064201000056)the Special Fund for Agro-scientific Research in the Public Interest(201003011)Specialized Research Fund for the Doctoral Program of Higher Education of China(20094404120012)
文摘Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of L-leucine, L-glutamate, L-tryptophan and L-arginine on feed intake and the mRNA expression levels of hypothalamic Neuropeptide involved in feed intake regulation in broiler chicks. Leucine, glutamate, tryptophan or arginine was intra-cerebroventricularly （ICV） administrated to 4d-old broiler chicks respectively and the feed intake were recorded at various time points. Quantitative PCR was performed to determine the hypothalamic mRNA expression levels of Neuropeptide Y （NPY）, agouti related protein （AgRP）, pro-opiomelanocortin （POMC）, melanocortin receptor 4 （MC4R） and corticotrophin releasing factor （CRF）. Our results showed that ICV administration of L-leucine （0.15 or 1.5 μmol） significantly （P〈0.05） increased feed intake up to 2 h post-administration period and elevated both hypothalamic NPY and AgRP mRNA expression levels. In contrast, ICV administration of L-glutamate （1.6 μmol） significantly （P 〈 0.05） decreased feed intake 0.25, 0.5 and 2 h post-injection, and increased hypothalamic CRF and MC4R mRNA expression levels. Meanwhile, both L-tryptophan （10 or 100 μg） and L-arginine （20 or 200 μg） had no significant effect on feed intake. These findings suggested that L-leucine and L-glutamate could act within the hypothalamus to influence food intake, and that both orexigenic and anorexigenic Neuropeptide genes might contribute directly to these effects.
