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M Rattray

Publications and source records attributed to M Rattray.

52 records · Page 3Linked to original sources
PubMed1993

Differential expression of GABA transporter-1 messenger RNA in subpopulations of GABA neurones.

Using in situ hybridisation with an oligonucleotide probe, the regional distribution of GABA transporter-1 messenger RNA was determined in the adult rat CNS. Overall, the distribution of GABA transporter-1 mRNA was similar to that of glutamate decarboxylase-67 mRNA, consistent with an expression in GABA neurones. However, in cerebellar cortex, Purkinje cells which express high levels of glutamate decarboxylase-67 mRNA did not express GABA transporter-1 mRNA, whereas Bergmann glia expressed GABA transporter-1 mRNA at high levels. In some other brain regions, including the inferior colliculus and reticular thalamus, there was no GABA transporter-1, although there were neurones which expressed glutamate decarboxylase-67 messenger RNA at high levels.

Animals↗
PubMed1993

Benzodiazepines increase preprocholecystokinin messenger RNA levels in rat brain.

Using in situ hybridisation, the effects of acute and chronic diazepam administration and diazepam withdrawal on preprocholecystokinin (CCK) mRNA levels in discrete regions of rat brain were determined. In cerebral cortex and a subpopulation of hippocampal neurones, CCK mRNA levels were increased after a single injection of diazepam and 24 h after withdrawal from chronic diazepam treatment, but not after chronic diazepam treatment. These results show that, in some neuronal groups, CCK mRNA expression is regulated by benzodiazepines, although there is no clear link between CCK mRNA levels and anxiety state.

Animals↗
PubMed1993

A combined in situ hybridization and immunofluorescence procedure allowing visualisation of peptide mRNA and serotonin in single sections.

We describe a novel procedure for combining immunocytochemistry with in situ hybridisation. In contrast to previously published procedures, the technique involves immunofluorescence followed by in situ hybridization and is particularly suitable for antigens which are labile or sensitive to in situ hybridization processing. We have evaluated the technique using 5-hydroxytryptamine (5-HT, serotonin) immunofluorescence and neuropeptide in situ hybridization employing 35S-labelled oligonucleotide probes. Successful double labelling was obtained and showed that galanin messenger RNA (mRNA) is expressed by 5-HT immunoreactive cells in the dorsal raphe nucleus of the rat. In contrast, somatostatin mRNA in the same region is expressed by a separate non-serotonergic cell population. Double-labelled preparations produced using this technique can be conveniently viewed using epipolarised combined with epifluorescent illumination. Careful analysis of procedural variables revealed that it is not possible to carry out high-sensitivity 5-HT immunocytochemistry following in situ hybridization. The immunostaining is much poorer on slide-mounted sections than on free-floating sections, and 5-HT appears to be lost during the in situ hybridization steps of dehydration/delipidation and incubation in hybridization buffer. The procedure we describe avoids these problems but with a slight loss of in situ hybridization sensitivity.

Animals↗
PubMed1992

Two populations of cells that express preprocholecystokinin mRNA in ventral periaqueductal grey.

Cells expressing preprocholecystokinin (CCK) mRNA in the rat midbrain periaqueductal grey area and Edinger-Westphal nucleus were analysed using in situ hybridization combined with liquid emulsion techniques. Semi-quantitative image analysis revealed that there were two populations of cells which expressed CCK mRNA. The first group of cells were large and heavily labelled and were confined to the Edinger-Westphal nucleus. The second group of cells were small and lightly labelled and were found scattered throughout ventral parts of the anterior periaqueductal grey.

Animals↗
PubMed1992

Intraperitoneal insulin is more potent than subcutaneous insulin at restoring hepatic insulin-like growth factor-I mRNA levels in the diabetic rat: a functional role for the portal vascular link.

There is evidence that the hormonal control of hepatic IGF-I production is mediated by GH and insulin. To elucidate the role of these hormones further we administered s.c. or i.p. insulin (at 2.5 and 5.0 IU/day) and/or GH (0.8 IU/day) to rats made diabetic with streptozotocin 16 days previously. Hepatic IGF-I production was then assessed by quantifying hepatic IGF-I mRNA levels by autoradiography of Northern blots. Diabetes resulted in a fivefold reduction in hepatic IGF-I mRNA levels (optical density (OD) of the 0.7-1.1 kb band: controls, 1.3 +/- 0.09; diabetics, 0.28 +/- 0.08; P < 0.01), which was not significantly changed by treatment with s.c. insulin (OD: low dose, 0.55 +/- 0.05; high dose, 0.58 +/- 0.05) or low dose i.p. insulin (OD: 0.40 +/- 0.03). High dose i.p. insulin enhanced hepatic IGF-I mRNA levels (OD: 0.93 +/- 0.23) compared with diabetic rats (P < 0.01) and those given high dose s.c. insulin (P < 0.04), despite the blood glucose values being similar in the treated groups (i.p., 4.72 +/- 0.29 mmol/l; s.c., 3.32 +/- 0.03 mmol/l). Administration of GH alone partially restored the hepatic IGF-I mRNA level (OD: GH-treated, 1.00 +/- 0.05; diabetic, 0.28 +/- 0.08; P < 0.01), whilst having no effect on blood glucose values (diabetic, 36.35 +/- 0.45 mmol/l; GH-treated, 38.65 +/- 2.39 mmol/l). Additional administration of s.c. insulin completely restored IGF-I mRNA levels to those of controls (OD: low dose, 1.35 +/- 0.14; high dose, 1.27 +/- 0.18).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Ligand autoradiographic receptor screening: receptor cDNA expression in replicas of transfected COS cells.

In this paper we validate a methodology, ligand autoradiographic receptor screening (LARS), for detecting expression of full length receptor cDNAs in COS cells. The method involves transfection of COS cells with receptor cDNAs by spheroplast fusion, production of filter replicas of the cell fragments, ligand binding to the receptors expressed in the membranes, and autoradiographic detection of bound ligand. A beta-adrenergic receptor cDNA cloned into a eukaryotic expression vector reliably induces high levels of beta-adrenergic receptor expression in 2-12% of COS cell colonies transfected with this plasmid after experimental conditions are optimized. Receptor expression is monitored by autoradiographic detection of 125iodocyanopindolol binding to COS cell fragments immobilized on polyester filter replicas. Binding displays appropriate pharmacological properties. The number of high-density binding spots per filter depends on the fraction of the spheroplasts in the fusion mixture that contain the beta-adrenergic receptor cDNA. A 100-plate LARS experiment can assess receptor expression in more than 10(4) transfected colonies. Thus detection of receptor-encoding sequences present in libraries in proportions as low as 1 in 10(4) should be possible. This technique may therefore be useful in detecting expression of other receptor cDNAs for which selective radioligands are available.

Animals↗
PubMed1988

The novel CCK antagonist L364,718 abolished caerulein- but potentiates morphine-induced antinociception.

The novel CCK antagonist L364,718 was tested on caerulein- and morphine-induced antinociception in rat using the paw pressure test. Caerulein-induced antinociception (ED50 = 30 micrograms/kg) was significantly inhibited by L354,718 (200 micrograms/kg i.p.) which on its own did not affect paw pressure threshold. In contrast, morphine-induced antinociception was significantly potentiated by L364,718. Since L364,718 is highly selective for 'peripheral' receptors which are found in tissue such as pancreas and gallbladder and a few discrete areas of brain, this receptor is likely to be implicated in the antinociceptive effect of caerulein.

Analgesics↗
PubMed1985

The metabolism of neuropeptides. Endopeptidase-24.11 in human synaptic membrane preparations hydrolyses substance P.

Synaptic membrane preparations from human striatum and human diencephalon were shown to contain a phosphoramidon-sensitive metalloendopeptidase that appeared identical with endopeptidase-24.11. The activity of endopeptidase-24.11 was determined with an enzymic assay employing [D-Ala2,Leu5]enkephalin as substrate, and its distribution in human brain was similar to that in pig brain, with the striatum containing the highest levels. The choroid plexus and pons also contained substantial activity. A good correlation (r = 0.97) was obtained for the distribution of the endopeptidase in pig brain and pituitary by the enzymic assay and by an immunoradiometric assay specific for pig endopeptidase-24.11. Synaptic membrane preparations from human striatum and diencephalon hydrolysed substance P at the same sites as did preparations of pig striatal synaptic membranes, and hydrolysis was substantially abolished by phosphoramidon. These results suggest that endopeptidase-24.11 is the principal enzyme hydrolysing substance P in human synaptic membrane preparations.

Animals↗
PubMed1979

Clinical course and diagnosis of genital herpes simplex virus infection and evaluation of topical surfactant therapy.

A prospective study of 37 men and 32 women with culture-proved genital herpes simplex virus (HSV) infection was undertaken to characterize the clinical manifestations of the disease and effects of topical therapy with Nonoxynol 9, a nonionic surfactant active in vitro against HSV. The duration of pain, lesions, and virus shedding was significantly longer in initial than in recurrent genital HSV infection. Cervical HSV shedding occurred in 11 of 13 initial infections versus two of 19 recurrences (p less than 0.001). Type 1 HSV caused seven of 29 initial and none of 40 recurrent infections (p less than 0.01). Clinical recurrences within six weeks were detected more often in men than in women and were unrelated to the menstrual cycle. The influence of coitus on recurrence is unclear. Papanicolaou smears were transiently abnormal (Class II) in four (12.5 per cent) of 32 female patients. Evidence of herpesvirus was detected cytologic smears from only 28 (41 per cent) of 69 culture-proved external lesions and three (23 per cent) of 13 culture-positive cervices. Serology was also of limited diagnostic value except in testing paired sera from initial infections. The topical therapy had no beneficial effect.

Adult↗
PubMedDate not supplied

Morphine action on cholecystokinin octapeptide release from rat periaqueductal grey slices: sensitisation by naloxone.

Cholecystokinin (CCK) has potent antinociceptive properties when given either peripherally or centrally. An interaction between opiate and CCK-induced antinociception is indicated as CCK-induced analgesia is potentiated by naloxone. Since CCK cells in Periaqueductal grey (PAG) are known to be sensitive to both noxious stimuli and i.v. morphine, the possibility that the PAG was the site of such an interaction was investigated by an in vitro study of the effects of morphine and naloxone on CCK release in PAG. The K+-evoked release of CCK from tissue slices of PAG was unaffected by a wide range of concentrations of morphine. However, after pretreatment with naloxone (10(-9) M), morphine (10(-7)-10(-6) M) caused a significant, dose dependent attenuation of CCK release (70% inhibition at 10(-6) M). These results suggest that the release of CCK in PAG is modulated by opioid systems.

Animals↗
PubMedDate not supplied

Caerulein-induced antinociception: interaction with morphine and opioid antagonists in the rat.

The relationship between CCK- and opioid-activated systems in antinociception is not clear. The effects of morphine, naloxone and naltrexone on the antinociceptive effect of systemically administered caerulein was determined using the paw pressure test in the rat. Caerulein treatment significantly increased paw pressure threshold with an ED50 of 30 micrograms/kg (22.2 nmol/kg) and was considerably more potent than morphine in this respect (ED50 of 882 nmol/kg). The opioid antagonists naloxone and naltrexone were found to potentiate the antinociceptive effect of caerulein (30 micrograms/kg) whilst abolishing the effect of morphine at doses of 3 micrograms/kg and above. Co-administration of caerulein (30 micrograms/kg) with low doses of morphine, normally ineffective in the paw pressure test, abolished caerulein-induced antinociception. However the effects of antinociceptive doses of morphine were depressed by caerulein (30 micrograms/kg), showing a mutual antagonism between caerulein and opioid activated effects. In contrast to these observations, morphine pre-injection (3h before testing) was found to significantly potentiate caerulein-induced antinociception revealing a differential interaction between opioid and CCK systems at different time points. The results indicate that CCK and opioids produce antinociception by separate, yet overlapping mechanisms.

Animals↗