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Intact neurotensin (NT) and dumping syndrome
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SUBSTANCE P-LIKE IMMUNOREACTIVITY (SP-LI) IN CAPSAICIN-SENSITIVE SENSORY TRIGEMINAL NEURONES INNERVATING THE RAT PAROTID. K. A. Sharkey and G.J. Dockray, MRC Secretory Control Group, Physiological Laboratory, University of Liverpool, Liverpool, UK. The undecapeptide substance P(SP) stimulates salivary secretion in the rat. It occurs in nerve fibres in rat salivary glands the origin of which is unknown. We have used immunohistochemistry coupled with retrograde tracing, employing the fluorescent dye True Blue (TB) to examine the possible sensory (trigeminal) origin of the SP in the rat parotid. True Blue (3~i, 5% suspension) was injected into the parotid of pentobarbitone anaesthetized rats. Five days later the rats were fixed by perfusion with 4% paraformaldehyde and cryostat sections of the parotid, trigeminal and superior cervical ganglia were examined. SP-LI was localized to nerve fibres around blood vessels and acinar tissue in the parotid. Unilateral injection of TB revealed labelled cells only in the ipsilateral trigeminal ganglion, 6.5~i.0% (n=4 rats) of the TB labelled cells also contained SP-LI. True Blue labelled cells were also observed in the superior cervical ganglia, but no SP-LI was seen in these cells. In rats treated neonatally with the sensory neurotoxin capsaicin there was a 50-60% reduction in TB labelled cells in the trigeminal ganglia and none of the remaining cells contained SP-LI. Within the gland there was a partial abolition of the SP-LI. Conclusions: i. The rat parotid possesses a trigeminal sensory innervation. 2. A sub-population of these sensory neurones contain SP-LI and are capsaicin sensitive. 3. The functional significance of the sensory SP in the control of secretion remains to be established.
INTACT NEUROTENSIN (NT) AND DUMPING SYNDROME C. Shaw I , P. C. H. Watt 2 and K. D. Buchanan I, Departments of Medicine I and Surgery 2, The Queen's University of Belfast. Neurotensin (NT) is a tridecapeptide with dual brain/gut localisation in mammals. In the human intestine, NT occurs in epithelial endocrine cells in the j ejuno-ileum. NT infusion in animals, at pharmacologic dosage, induces a profound hypotension. As subjects with dumping syndrome exhibit postprandial changes in blood pressure and have enhanced NT secretion it has been proposed that NT is the causative agent. Six patients with dumping syndrome (age 58± 3.7 yrs) were given a 75 g OGTT and a standard mixed meal (50 g CHO, 18 g protein, 15 g fat) on separate days and in random order. Blood samples were drawn from a cubital vein for NT radioimmunoassay using a system which measures only intact NT. Dumping symptoms were scored at the time of each blood sample according to the index of Sigstad (1970). Basal NT prior to 75 g OGTT was 10.21±1.73 pmol. i.-i and rose to a peak of 87.17±21.73 pmol. i. -I at 15 min. Mean dumping score at this time was 17.5±1.9. Basal NT prior to SMM was 11.21± 0.93 pmol. i. -I and rose to a peak of 116.31±45.33 pmol. i. -l at 30 min. Mean dumping score at this time was 8.8±3.2. Peak levels of intact NT were not significantly different (p<0.3) but mean dumping scores were (p
SUBSTANCE P-LIKE IMMUNOREACTIVITY (SP-LI) IN CAPSAICIN-SENSITIVE SENSORY TRIGEMINAL NEURONES INNERVATING THE RAT PAROTID. K. A. Sharkey and G.J. Dockray, MRC Secretory Control Group, Physiological Laboratory, University of Liverpool, Liverpool, UK. The undecapeptide substance P(SP) stimulates salivary secretion in the rat. It occurs in nerve fibres in rat salivary glands the origin of which is unknown. We have used immunohistochemistry coupled with retrograde tracing, employing the fluorescent dye True Blue (TB) to examine the possible sensory (trigeminal) origin of the SP in the rat parotid. True Blue (3~i, 5% suspension) was injected into the parotid of pentobarbitone anaesthetized rats. Five days later the rats were fixed by perfusion with 4% paraformaldehyde and cryostat sections of the parotid, trigeminal and superior cervical ganglia were examined. SP-LI was localized to nerve fibres around blood vessels and acinar tissue in the parotid. Unilateral injection of TB revealed labelled cells only in the ipsilateral trigeminal ganglion, 6.5~i.0% (n=4 rats) of the TB labelled cells also contained SP-LI. True Blue labelled cells were also observed in the superior cervical ganglia, but no SP-LI was seen in these cells. In rats treated neonatally with the sensory neurotoxin capsaicin there was a 50-60% reduction in TB labelled cells in the trigeminal ganglia and none of the remaining cells contained SP-LI. Within the gland there was a partial abolition of the SP-LI. Conclusions: i. The rat parotid possesses a trigeminal sensory innervation. 2. A sub-population of these sensory neurones contain SP-LI and are capsaicin sensitive. 3. The functional significance of the sensory SP in the control of secretion remains to be established.
INTACT NEUROTENSIN (NT) AND DUMPING SYNDROME C. Shaw I , P. C. H. Watt 2 and K. D. Buchanan I, Departments of Medicine I and Surgery 2, The Queen's University of Belfast. Neurotensin (NT) is a tridecapeptide with dual brain/gut localisation in mammals. In the human intestine, NT occurs in epithelial endocrine cells in the j ejuno-ileum. NT infusion in animals, at pharmacologic dosage, induces a profound hypotension. As subjects with dumping syndrome exhibit postprandial changes in blood pressure and have enhanced NT secretion it has been proposed that NT is the causative agent. Six patients with dumping syndrome (age 58± 3.7 yrs) were given a 75 g OGTT and a standard mixed meal (50 g CHO, 18 g protein, 15 g fat) on separate days and in random order. Blood samples were drawn from a cubital vein for NT radioimmunoassay using a system which measures only intact NT. Dumping symptoms were scored at the time of each blood sample according to the index of Sigstad (1970). Basal NT prior to 75 g OGTT was 10.21±1.73 pmol. i.-i and rose to a peak of 87.17±21.73 pmol. i. -I at 15 min. Mean dumping score at this time was 17.5±1.9. Basal NT prior to SMM was 11.21± 0.93 pmol. i. -I and rose to a peak of 116.31±45.33 pmol. i. -l at 30 min. Mean dumping score at this time was 8.8±3.2. Peak levels of intact NT were not significantly different (p<0.3) but mean dumping scores were (p