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Quantification of an increase in neuropeptide Y-immunoreactive nerves in the paraventricular nucleus of the streptozotocin-diabetic rat
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QUANTIFICATION OF AN INCREASE IN NEUROPEPTIDE Y-IMMUNOREACTIVE NERVES IN THE PARAVENTRICULAR NUCLEUS OF THE STREPTOZOTOCIN-DIABETIC RAT J.H. STEEL1, T.J. BENTLEYI , G. WILLIAMS2, H. CARDOSO2, S.R. BLOOM2, J.M POLAK1, Departments of HistochemistryI and Mediclnez, Royal Postgraduate Medical School, Du Cane Road, London WI20NN, U.K. Using radioimmunoassay i t has been shown that hypothalamic neuropeptide Y (NPY)-like immunoreactivity (IR) is significantly raised in streptozotocin (STZ)-diabetic rats (Williams et al, 1988, Diabetes, in press). These findings were investigated immunocytochemically. Wistar rats treated with SIY or saline were killed 6 weeks l a t e r . Brains were perfused with Bouin's f l u i d , and serial coronal cryostat sections (20~m) were immunostained for NPY and C-terminal flanking peptide of NPY (CPON) using the PAP method with cobalt chloride intensification. Intensely NPY-IR and CPON-IR, large and distorted cell bodies were seen in the supraoptic nucleus (SON) of SlYdiabetic rats whereas no NPY-IR or CPON-IR cells were seen in the SON of controls. To investigate whether there was also an increase in hypothalamic CPON-IR nerve fibres the area of the CPON-IR paraventricular nucleus (PVN) terminal f i e l d was measured in S1-Z-treated and control rats using an IBAS image analyser (Kontron). The maximumcoronal PVN area was found for each animal by outlining the CPON-IR PVN in successive sections. A significant increase in mean staine~ PVN area was seen in STZ-diabetic rats (STZ O.69mm2 ± 0.027, control O.5gmm( ± 0.025; mean ~ SEM: P 0.05), indicating that there is a genuine increase in NPY-containing nerves. In preliminary studies by Northern gel, an increase in hypothalamic NPY mRNAlevels was shown in SI-Z-diabetic rats (Pierson et al, 1988, British Diabetic Association Abstract). We conclude that in the hypothalamus of SIZ-diabetic rats there is an increase in NPY gene expression and peptide content.
PEPTIDES IN HUMAN PERIPHERAL VASCULATURE
S. THOM, Ao HUGHES, G. MARTIN, H. NIELSEN, P. INKPEN, M. SCHACHTER, P. SEVER. Clinical Pharmacology, St. Mary's Hospital Medical School, London, W.2. The direct effects of peptides with potential vasoregulatory roles have been compared in conduit and resistance arteries. Ring segments (!D 2-4 ram) of ~planchnic, peripheral, coronary, pulmonary and uterine arteries, obtained at surgery, were studied in the organ bath, and resistance vessels (ID 120-400 ~M) from subcutaneous fat and omentum in the Mulvany myograph. Noradrenaline (NA) or serotonin were used as preeonstricting agents. The intesrity of the endothelium was established, where relevant, by relaxatory responses to A23187 or acetylcholine. NPY constricted resistance vessels (n = 7). The contraction produced at I00 nM was equal to that induced by NA (i0 ~M). Marked tachyphylaxis was evident after a single response. Coronary arteries (n = 5) did not respond to NPY. ANP (i00 n M - i ~M) produced a concentrationdependent relaxatioiL of preconstricted conduit arteries regardless of site and independent of endotheli~m, h~t preliminary results in microvessels (n = 4) show no response. CGRP (10-v-10-VM) relaxed conduit arteries (n = 14) in an endothelium-dependent manner which was reversible by haemoglobin, but in contrast the relaxation of resistance arteries (n = 7) was independent of endothelium. There are major individual differences between the conduit and the resistance vessels for each of these pepZides. This highlights the inadequacy of large vessel systems as overall models of the vasculature.
QUANTIFICATION OF AN INCREASE IN NEUROPEPTIDE Y-IMMUNOREACTIVE NERVES IN THE PARAVENTRICULAR NUCLEUS OF THE STREPTOZOTOCIN-DIABETIC RAT J.H. STEEL1, T.J. BENTLEYI , G. WILLIAMS2, H. CARDOSO2, S.R. BLOOM2, J.M POLAK1, Departments of HistochemistryI and Mediclnez, Royal Postgraduate Medical School, Du Cane Road, London WI20NN, U.K. Using radioimmunoassay i t has been shown that hypothalamic neuropeptide Y (NPY)-like immunoreactivity (IR) is significantly raised in streptozotocin (STZ)-diabetic rats (Williams et al, 1988, Diabetes, in press). These findings were investigated immunocytochemically. Wistar rats treated with SIY or saline were killed 6 weeks l a t e r . Brains were perfused with Bouin's f l u i d , and serial coronal cryostat sections (20~m) were immunostained for NPY and C-terminal flanking peptide of NPY (CPON) using the PAP method with cobalt chloride intensification. Intensely NPY-IR and CPON-IR, large and distorted cell bodies were seen in the supraoptic nucleus (SON) of SlYdiabetic rats whereas no NPY-IR or CPON-IR cells were seen in the SON of controls. To investigate whether there was also an increase in hypothalamic CPON-IR nerve fibres the area of the CPON-IR paraventricular nucleus (PVN) terminal f i e l d was measured in S1-Z-treated and control rats using an IBAS image analyser (Kontron). The maximumcoronal PVN area was found for each animal by outlining the CPON-IR PVN in successive sections. A significant increase in mean staine~ PVN area was seen in STZ-diabetic rats (STZ O.69mm2 ± 0.027, control O.5gmm( ± 0.025; mean ~ SEM: P 0.05), indicating that there is a genuine increase in NPY-containing nerves. In preliminary studies by Northern gel, an increase in hypothalamic NPY mRNAlevels was shown in SI-Z-diabetic rats (Pierson et al, 1988, British Diabetic Association Abstract). We conclude that in the hypothalamus of SIZ-diabetic rats there is an increase in NPY gene expression and peptide content.
PEPTIDES IN HUMAN PERIPHERAL VASCULATURE
S. THOM, Ao HUGHES, G. MARTIN, H. NIELSEN, P. INKPEN, M. SCHACHTER, P. SEVER. Clinical Pharmacology, St. Mary's Hospital Medical School, London, W.2. The direct effects of peptides with potential vasoregulatory roles have been compared in conduit and resistance arteries. Ring segments (!D 2-4 ram) of ~planchnic, peripheral, coronary, pulmonary and uterine arteries, obtained at surgery, were studied in the organ bath, and resistance vessels (ID 120-400 ~M) from subcutaneous fat and omentum in the Mulvany myograph. Noradrenaline (NA) or serotonin were used as preeonstricting agents. The intesrity of the endothelium was established, where relevant, by relaxatory responses to A23187 or acetylcholine. NPY constricted resistance vessels (n = 7). The contraction produced at I00 nM was equal to that induced by NA (i0 ~M). Marked tachyphylaxis was evident after a single response. Coronary arteries (n = 5) did not respond to NPY. ANP (i00 n M - i ~M) produced a concentrationdependent relaxatioiL of preconstricted conduit arteries regardless of site and independent of endotheli~m, h~t preliminary results in microvessels (n = 4) show no response. CGRP (10-v-10-VM) relaxed conduit arteries (n = 14) in an endothelium-dependent manner which was reversible by haemoglobin, but in contrast the relaxation of resistance arteries (n = 7) was independent of endothelium. There are major individual differences between the conduit and the resistance vessels for each of these pepZides. This highlights the inadequacy of large vessel systems as overall models of the vasculature.