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Arginyl-aminopeptidase activity in discrete areas of the rat and the human brain
s90 P8-6
P8-8
The effect of total water deprivation on the natriuretic peptide system of the hopping mouse,
Notomvs
alexis
Donald JA, Davis B, Minerds KL, and Toop T School of Biological and Chemical Sciences, Deakin University, Geelong, Australia, 3217 The natriuretic peptide system counters hypervolaemia and concomitant hypertension by renal diuresis and natriuresis, and vasodilation. However, the importance of hypervolaemic regulation in mammals has been questioned, and in particular, the role of natriuretic peptides in the maintenance of normal fluid balance. We are using the hopping mouse, Notomys alexis, to investigate the function of natriuretic peptides in a desert-adapted mammal that can survive without free access to water. Atrial natriuretic peptide (ANP) cDNA was cloned from N. alexis, and the sequence of ANP (l-28) was identical to rat ANP. This enabled a homologous radioimmunoassay for rat ANP to be used to quantify ANP levels in the heart and plasma of N. &. N. &&, of either sex, were divided into an experimental group (n=12) subject to seventeen days of total water deprivation (TWD), and a control group (n=12) that had free access to water. No significant difference in plasma osmolarity, haematocrit, skeletal muscle and liver water content, and cardiac ANP levels was observed between control and experimental groups. However, plasma ANP and the density of ANP binding on renal glomeruli were significantly lower in TWD animals when compared to control animals. This data suggests that the ANP system is down-regulated during TWD, probably to conserve salt and water.
oto M’, Wang XY’, Sat&e Hz, Morishita F3 and
Matsushima 0’ Shimane
‘Department of Biological Science, LES,
University,
Matsue
Institute for Bioorganic ‘Department
Japan
Research,
of Biological
690-8504,
‘Suntory
Osaka Japan 618-8503,
Science,
Faculty
of
Science,
Hiroshima University, Higashihiroshima 739-8526 Japan.
A new RFamide, (C-RFa) isolated from the brain of the crucian carp, was examined for its distribution and effect on the retinal cell responses. C-RFa hyperpolarized the membrane of the Ltype horizontal cells, slightly increased the S-potentials and depolarized some amacrine cells. The abundant presence of the C-RFa mRNA was demonstrated in the eyecup by Southern blot analysis of the RT-PCR product. It was also revealed that the C-RFa-immunoreactivity
was shown to be localized in the
distal portion of the innerplexiform
layer (IPL). These results
show that C-RFa is actually present in the retina and is involved in the synaptic systems in the lPL. We assume that the horizontal cell responses are indirectly modified via the CRFa-sensitive neurons. P8-10
Effects of food deprivation on neuropeptide Y (NPY) gene expression and GH secretion in goldfish (Carassius auratus.)
P8-7
Arginyl-aminopeptidase and the human brain.
The effect of a novel RFamide isolated from the brain of the Japanese crucian carp on the retinal cell responses.
activity in discrete areas of the rat
Fern6ndezD; Irazusta J; AguirregoitiaN, Ruiz F and CasisL Department of Physiology, Medical School, University of the Basque Country, Leioa (SPAIN) Neuropeptide activity is regulated via their inactivation by several peptidases. Among these enzymes, the arginylaminopeptidase can degraded various physiological active peptides such as Met-enkephalin, angiotensin III and somatostatine.Althoughthis enzyme is an exopeptidase,it shows also an endopeptidase activity degrading several peptides like bradykinin,angiotensii I and neurotensin. In this report, we have measured arginyl-aminopeptide activity in several regions of the human and rat brain. Arginylaminopeptidase activity was measured fluorimetrically in the soluble fraction using Arg-p-naphtilamideas substrate. In order to avoid the action of other aminopeptidases the enzymatic assay was carried out at pH 6.5 and in the presence of the inhibitor puromycin (20 @I). In this study we have found that in the rat brain the arginylaminopeptidase activity levels are significantly higher in amygdala, striatum, frontal and occipital cortiees than in the human brain. These results suggest that arginyl-aminopeptidase could be involved in a different way in the regulation of the neuropeptide levels in the human and in the rat brain.
Narnaware YK, Peyon P, Lin X and Peter RE Department of Biological Sciences, University Edmonton, Alberta, T6G 2E9 Canada.
of Alberta,
Neuropeptide Y (NPY) is well known for its role in regulation of daily feeding patterns in mammals. In the present study, the effects of disturbances of the regular daily feeding pattern, by food deprivation for 24-72h, on NPY gene expression in goldfish were studied. Goldfish deprived of food for 24h-48h did not have a significant change in NPY mRNA expression in either the telencephalon-POA or optic tectum-thalamus; however, 72h food deprivation caused a two-fold increase in NPY mRNA expression in both brain regions. The hypothalamus displayed a time-dependent and significant increase in NPY mRNA expression in response to 24h and 48h of food deprivation, with a lo-fold increase in 72h food-deprived group. Serum GH levels were significantly higher in all food-deprived groups when compared to fed controls. Refeeding at 1h and 3h after 72h of food deprivation did not restore NPY expression to levels found in controls in either the telencephalon-POA or hypothalamus. In the optic tectum-thalamus, NPY mRNA expression was still significantly higher after lh of re-feeding, but was restored to controls after 3h. These data indicate that NPY has a role in regulation of feeding and GH secretion in goldfish.
P8-8
The effect of total water deprivation on the natriuretic peptide system of the hopping mouse,
Notomvs
alexis
Donald JA, Davis B, Minerds KL, and Toop T School of Biological and Chemical Sciences, Deakin University, Geelong, Australia, 3217 The natriuretic peptide system counters hypervolaemia and concomitant hypertension by renal diuresis and natriuresis, and vasodilation. However, the importance of hypervolaemic regulation in mammals has been questioned, and in particular, the role of natriuretic peptides in the maintenance of normal fluid balance. We are using the hopping mouse, Notomys alexis, to investigate the function of natriuretic peptides in a desert-adapted mammal that can survive without free access to water. Atrial natriuretic peptide (ANP) cDNA was cloned from N. alexis, and the sequence of ANP (l-28) was identical to rat ANP. This enabled a homologous radioimmunoassay for rat ANP to be used to quantify ANP levels in the heart and plasma of N. &. N. &&, of either sex, were divided into an experimental group (n=12) subject to seventeen days of total water deprivation (TWD), and a control group (n=12) that had free access to water. No significant difference in plasma osmolarity, haematocrit, skeletal muscle and liver water content, and cardiac ANP levels was observed between control and experimental groups. However, plasma ANP and the density of ANP binding on renal glomeruli were significantly lower in TWD animals when compared to control animals. This data suggests that the ANP system is down-regulated during TWD, probably to conserve salt and water.
oto M’, Wang XY’, Sat&e Hz, Morishita F3 and
Matsushima 0’ Shimane
‘Department of Biological Science, LES,
University,
Matsue
Institute for Bioorganic ‘Department
Japan
Research,
of Biological
690-8504,
‘Suntory
Osaka Japan 618-8503,
Science,
Faculty
of
Science,
Hiroshima University, Higashihiroshima 739-8526 Japan.
A new RFamide, (C-RFa) isolated from the brain of the crucian carp, was examined for its distribution and effect on the retinal cell responses. C-RFa hyperpolarized the membrane of the Ltype horizontal cells, slightly increased the S-potentials and depolarized some amacrine cells. The abundant presence of the C-RFa mRNA was demonstrated in the eyecup by Southern blot analysis of the RT-PCR product. It was also revealed that the C-RFa-immunoreactivity
was shown to be localized in the
distal portion of the innerplexiform
layer (IPL). These results
show that C-RFa is actually present in the retina and is involved in the synaptic systems in the lPL. We assume that the horizontal cell responses are indirectly modified via the CRFa-sensitive neurons. P8-10
Effects of food deprivation on neuropeptide Y (NPY) gene expression and GH secretion in goldfish (Carassius auratus.)
P8-7
Arginyl-aminopeptidase and the human brain.
The effect of a novel RFamide isolated from the brain of the Japanese crucian carp on the retinal cell responses.
activity in discrete areas of the rat
Fern6ndezD; Irazusta J; AguirregoitiaN, Ruiz F and CasisL Department of Physiology, Medical School, University of the Basque Country, Leioa (SPAIN) Neuropeptide activity is regulated via their inactivation by several peptidases. Among these enzymes, the arginylaminopeptidase can degraded various physiological active peptides such as Met-enkephalin, angiotensin III and somatostatine.Althoughthis enzyme is an exopeptidase,it shows also an endopeptidase activity degrading several peptides like bradykinin,angiotensii I and neurotensin. In this report, we have measured arginyl-aminopeptide activity in several regions of the human and rat brain. Arginylaminopeptidase activity was measured fluorimetrically in the soluble fraction using Arg-p-naphtilamideas substrate. In order to avoid the action of other aminopeptidases the enzymatic assay was carried out at pH 6.5 and in the presence of the inhibitor puromycin (20 @I). In this study we have found that in the rat brain the arginylaminopeptidase activity levels are significantly higher in amygdala, striatum, frontal and occipital cortiees than in the human brain. These results suggest that arginyl-aminopeptidase could be involved in a different way in the regulation of the neuropeptide levels in the human and in the rat brain.
Narnaware YK, Peyon P, Lin X and Peter RE Department of Biological Sciences, University Edmonton, Alberta, T6G 2E9 Canada.
of Alberta,
Neuropeptide Y (NPY) is well known for its role in regulation of daily feeding patterns in mammals. In the present study, the effects of disturbances of the regular daily feeding pattern, by food deprivation for 24-72h, on NPY gene expression in goldfish were studied. Goldfish deprived of food for 24h-48h did not have a significant change in NPY mRNA expression in either the telencephalon-POA or optic tectum-thalamus; however, 72h food deprivation caused a two-fold increase in NPY mRNA expression in both brain regions. The hypothalamus displayed a time-dependent and significant increase in NPY mRNA expression in response to 24h and 48h of food deprivation, with a lo-fold increase in 72h food-deprived group. Serum GH levels were significantly higher in all food-deprived groups when compared to fed controls. Refeeding at 1h and 3h after 72h of food deprivation did not restore NPY expression to levels found in controls in either the telencephalon-POA or hypothalamus. In the optic tectum-thalamus, NPY mRNA expression was still significantly higher after lh of re-feeding, but was restored to controls after 3h. These data indicate that NPY has a role in regulation of feeding and GH secretion in goldfish.