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Biomedical subjects

G Milligan

Publications and source records attributed to G Milligan.

At least 181 records · Page 10Linked to original sources
PubMed1993

Regional distribution and quantitative measurement of the phosphoinositidase C-linked guanine nucleotide binding proteins G11 alpha and Gq alpha in rat brain.

Levels of the guanine nucleotide binding proteins G11 alpha and Gq alpha, which produce receptor regulation of phosphoinositidase C, were measured immunologically in 13 regions of rat central nervous system. This was achieved by immunoblotting membranes from these regions with antisera (CQ series) that identify these two polypeptides equally, following separation of the membranes using sodium dodecyl sulphate-polyacrylamide gel electrophoresis conditions that can resolve Gq alpha and G11 alpha. In all regions examined, Gq alpha was more highly expressed than G11 alpha. Ratios of levels of Gq alpha to G11 alpha varied between the regions from 5:1 to 2:1. Quantitative measurements of the levels of Gq alpha and G11 alpha in each region were obtained by comparison with known amounts of purified liver Gq alpha and G11 alpha and with E. coli expressed recombinant Gq alpha. Areas that expressed Gq alpha highly included olfactory bulb (930 ng/mg of membrane protein), frontal cortex (700 ng/mg of membrane protein), parietal occipital cortex (670 ng/mg of membrane protein), caudate putamen (1,003 ng/mg of membrane protein), hippocampus (1,045 ng/mg of membrane protein), hypothalamus (790 ng/mg of membrane protein), and cerebellum (950 ng/mg of membrane protein). More modest levels were observed in thalamus (450 ng/mg of membrane protein), pituitary (480 ng/mg of membrane protein), optic chiasma (330 ng/mg of membrane protein), and spinal cord (350 ng/mg of membrane protein). G11 alpha was more evenly expressed with values ranging from about 170 ng/mg of membrane protein in spinal cord and optic chiasma to close to 300 ng/mg of membrane protein in regions expressing high levels of Gq alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Radiographic progression of hospital referred osteoarthritis of the hip.

Various factors have been considered important in the rate of progression of osteoarthritis of the hip, though few data are available from large longitudinal studies. One hundred and thirty six patients referred to hospital (85 women, 51 men; mean age 65 years, range 29-86 years) with osteoarthritis of the hip (192 affected hips) were followed up for a median of 27 (range 3-72) months. One hundred and six patients (144 affected hips) were reviewed for a minimum of one year (median 28, range 12-72 months). Fifty three per cent of all osteoarthritic hips required an operation at a median of 14 (range 3-48) months from entry. All radiographs before and after entry were examined (median four films for each patient over a median of three years, range 0.5-19 years). Hips showing rapid radiographic progression on prospective films more often had superior migration, or an atrophic bone response; those with no progression more often had an indeterminate, medial, or axial migration pattern, protrusio or mild osteoarthritis at presentation. A higher occurrence of rapid progression was seen in women, in those of older age at symptom onset, and in hips with a higher Kellgren grade at entry; men more often showed no progression. Age at presentation, body mass index, symptom duration, or presence of chondrocalcinosis, hand osteoarthritis/nodes, or Forestier's disease did not influence progression. This study supports the contention that, at the time of hospital referral, certain patient characteristics and radiographic features at the hip may help to identify those at high risk of rapidly progressive hip osteoarthritis.

Adult↗
PubMed1993

Guanine nucleotide regulatory proteins in the spontaneously hypertensive rat.

We compared guanine nucleotide regulatory protein (G protein) levels and function in plasma membranes from resistance vessels (mesenteric arteries) isolated from spontaneously hypertensive (SHR) and normotensive Wistar rats. G protein function was deduced from studies of adenylate cyclase activity. Although the basal level of adenylate cyclase activity (+/- Mn2+ ions) was significantly greater in SHR membranes, addition of agents that function via the stimulatory G protein--i.e., NaF (10(-2) M), (-)-isoproterenol (10(-4) M), and prostaglandin E1 (10(-5) M)--resulted in a significantly lower stimulatory response in SHR membranes. Ligands that function via the inhibitory G protein--i.e., adrenaline (10(-5) M)/propranolol (10(-5) M) (this combination being equivalent to an alpha 2-receptor agonist), carbachol (10(-3) M), and serotonin (10(-5) M)--were responsible for only slight inhibitory responses in both SHR and Wistar rat membranes, which were not significantly different. Western blotting identified the presence of Gs, Gi2, and Gi3 alpha-subunits in rat vascular smooth muscle, but there were no differences in the levels of these G protein alpha-subunits found in SHR and Wistar rat plasma membranes. The levels of the beta-subunit in the two sets of membranes were also similar. In conclusion, there is a reduced response in adenylate cyclase activity to agents that function via the stimulatory G protein in SHR membranes. However, this is not a consequence of altered levels of the different G protein subunits.

Adenylyl Cyclases↗
PubMed1993

Characterization of the gonadotrophin-releasing hormone receptor in alpha T3-1 pituitary gonadotroph cells.

The present study has characterized the gonadotrophin-releasing hormone (GnRH) receptor in immortalized alpha T3-1 pituitary gonadotroph cells. GnRH and GnRH analogues produced both a dose- and time-dependent increase in total inositol phosphate (IP) accumulation. The rank order of potency of these analogues was the same as that obtained in parallel receptor-binding studies in alpha T3-1 cells. These responses were abolished following pretreatment with a GnRH antagonist. The use of a specific inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) assay demonstrated a rapid but short-lived rise in Ins(1,4,5)P3 production. Intracellular calcium ([Ca2+]i) was subsequently measured in alpha T3-1 cells using dual wavelength fluorescence microscopy combined with dynamic video imaging. GnRH produced a biphasic rise in [Ca2+]i. The initial calcium transient was complete within seconds while the smaller secondary plateau phase lasted several minutes. G-protein involvement in the IP response to GnRH in alpha T3-1 cells was investigated using sodium fluoride (NaF) and pertussis toxin (PTx) which activate and inactivate G-proteins respectively. Like GnRH, NaF produced a dose- and time-dependent increase in IP accumulation. Activation of phospholipase C in these cells by either GnRH or NaF was PTx-insensitive, suggesting that the G-protein involved was neither Gi nor Go but more probably Gq. Immunoblot analysis of alpha T3-1 cell membranes using antisera raised against the predicted C-terminal decapeptide of the alpha subunit of Gq demonstrated the presence of Gq in alpha T3-1 cells. Collectively these results show that the GnRH receptors expressed in alpha T3-1 cells are coupled to the phosphatidylinositol second messenger pathway via a specific G-protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Buserelin↗
PubMed1993

Guanine nucleotide regulatory protein alterations in the Milan hypertensive rat strain.

OBJECTIVE: To examine whether the altered regulation of adenylyl cyclase that has been reported in vascular tissues from spontaneously hypertensive rats is also evident in the Milan hypertensive (MHS) rat strain. DESIGN: The plasma membranes of vascular smooth muscle cells derived from thoracic aortae from adult (60-day-old) MHS and Milan normotensive (MNS) strain rats were studied. METHODS: Guanine nucleotide regulatory protein (G-protein) function was inferred from adenylyl cyclase activity studies, and levels of G-protein subunits were assessed by immunoblotting. beta-Adrenergic receptor number and affinity were measured from the binding of the antagonist [125I]-cyanopindolol. RESULTS: Basal adenylyl cyclase activity was increased significantly in MHS rat cell membranes, and stimulation by 0.1 mmol/l isoproterenol and 0.01 mmol/l prostaglandin E1 was significantly greater in MHS than in MNS rat cell membranes. Forskolin (at 0.1 mmol/l) resulted in a significantly greater stimulatory response in MHS membranes, which was eliminated by 0.01 mol/l NaF. Biphasic effects of GTP on isoproterenol-stimulated membranes demonstrated similar Gi function in MHS and MNS rat cell membranes, although a greater stimulatory GTP response was observed in MHS rat cell membranes. The levels of Gs alpha (both forms), Gi3 alpha and the beta-subunit were reduced in MHS rat cell membranes, whereas the levels of Gi2 alpha and Gq alpha and G11 alpha were unchanged. The number of beta-adrenoceptors was increased significantly in MHS rat cell membranes, whereas receptor affinity for the antagonist was unaltered. CONCLUSIONS: There are differences in adenylyl cyclase stimulatory responses in MHS rat vascular smooth muscle cell membranes. We have found evidence of reduced levels of particular G-protein subunits, altered beta-adrenoceptor-Gs coupling and increased beta-adrenoceptor number.

Adenylyl Cyclases↗
PubMed1993

Direct measurements of in situ interactions of rat brain opioid receptors with the guanine nucleotide-binding protein Go.

The interactions of rat brain cortical opioid receptors with the guanine nucleotide-binding protein (G protein) Go were probed in membranes by examining the ability of selective antipeptide anti-G protein antisera to disrupt receptor-G protein interactions. This was measured both by antibody-induced alterations in the characteristics of agonist binding to mu and delta receptor binding sites and by antibody attenuation of opioid stimulation of high affinity GTPase activity. Antisera to the amino-terminal 16 amino acids (ON1), amino acids 22-35 (IM1), and the carboxyl-terminal decapeptide (OC2) of forms of Go alpha were able to selectively immunoprecipitate Go from rat cortical membranes. Both antisera OC2 and ON1 were able to immunoprecipitate Go alpha quantitatively. Preincubation of rat cortical membranes with an IgG fraction isolated from antiserum OC2 was able to produce a marked reduction in the ability of the synthetic enkephalin [D-Ala2,D-Leu5] enkephalin (DADLE) (which interacts with delta and mu but not significantly with kappa receptors) to displace specific binding of [3H] diprenorphine (which binds to all of these sites), demonstrating a clear interaction of the mu and delta receptors with one or more variants of Go. An IgG fraction from antiserum ON1 was able to mimic this effect, suggesting that the amino-terminal region of G protein alpha subunits also plays a role in receptor-G protein interactions. In contrast, an IgG fraction from antiserum IM1 was unable to alter the characteristics of DADLE displacement of [3H] diprenorphine binding. Similarly, an antiserum (SG1) directed against the carboxyl-terminal decapeptide common to the alpha subunits of Gi1 and Gi2 was unable to reduce the affinity of DADLE binding to opioid receptors. Use of antiserum OC2 in experiments that allowed pharmacological examination of only the mu-opioid receptor provided independent evidence for the interaction of this receptor site with Go.

Amino Acid Sequence↗
PubMed1992

Guanine nucleotide regulatory protein levels and function in spontaneously hypertensive rat vascular smooth-muscle cells.

We compared G-protein levels and function in membranes from vascular smooth-muscle cells (VSMC) derived from mesenteric arteries from SHR, WKY and Wistar rats. Basal adenylyl cyclase activity was significantly reduced in SHR membranes compared with Wistar, but was similar to WKY. Isoproterenol stimulation (10(-4) M) was significantly lower in SHR membranes compared to WKY, but was similar to that in Wistar, which was also significantly lower than WKY. Forskolin (10(-4) M) and NaF (10(-2) M), resulted in a higher stimulatory response in SHR membranes. Biphasic effects of GTP on isoproterenol-stimulated membranes demonstrated unaltered Gi function in SHR membranes. No significant differences were seen in the levels of Gs alpha (44- and 42-kDa forms), Gi2 alpha and the beta-subunit in immunoblotting studies of the membranes. Amounts of Gq alpha/G11 alpha and Gi3 alpha were also unchanged. In conclusion, there are differences in adenylyl cyclase responses in SHR VSMC membranes which are not a consequence of altered levels of G-proteins, but may reflect genetic differences rather than effects of hypertension.

Adenylyl Cyclases↗
PubMed1992

Concurrent down-regulation of IP prostanoid receptors and the alpha-subunit of the stimulatory guanine-nucleotide-binding protein (Gs) during prolonged exposure of neuroblastoma x glioma cells to prostanoid agonists. Quantification and functional implications.

Neuroblastoma x glioma hybrid NG108-15 cells express a high-affinity IP prostanoid receptor. Saturation binding analysis of this receptor, using [3H]prostaglandin E1 ([3H]PGE1) as ligand, indicated that it was present at some 1.5 pmol/mg of membrane protein and displayed a dissociation constant for this ligand of 30-40 nM. Prolonged exposure of these cells either to PGE1 or to iloprost, which is a stable analogue of prostacyclin, caused a 40-70% decrease in levels of the receptor. The remaining receptors were capable of interacting with the stimulatory G-protein (Gs) of the adenylate cyclase cascade, as saturation analysis of the binding of [3H]PGE1 indicated that they had a similar affinity for the 3H-labelled ligand, and because the specific binding of [3H]PGE1 to these receptors was still sensitive to the presence of poorly hydrolysed analogues of GTP. We have recently demonstrated that prolonged exposure of NG108-15 ells to PGE1 causes a cyclic AMP-independent loss of Gs alpha-subunit (Gs alpha) from these cells [McKenzie & Milligan (1990) J. Biol. Chem. 265, 17084-17093]. Steady-state concentration of the larger 45 kDa form of Gs alpha (which is the predominant form expressed in these cells) was assessed to be 9.6 pmol/mg of membrane protein, and treatment with iloprost decreased levels of this polypeptide to some 3.0 pmol/mg of protein. Time courses of iloprost-mediated down-regulation of the IP prostanoid receptor, loss of Gs alpha protein as assessed by immunoblotting and loss of Gs alpha activity as assessed by the reconstitution of NaF stimulation of adenylate cyclase activity to membranes of S49 cyc- cells by sodium cholate extracts of NG108-15 cells were identical, suggesting that the loss of the IP prostanoid receptor and G-protein occurred in parallel. Each of these effects was half-maximal between 2 and 3 h of exposure to the agonist. Stoichiometry of loss of Gs alpha and IP prostanoid receptor was unchanged by the percentage receptor occupancy, and quantification indicated the loss of some 7-10 mol of Gs alpha/mol of receptor. This is the first report to demonstrate the temporal concurrence of loss of Gs alpha and of a receptor which interacts with this G-protein. Chronic activation of the IP prostanoid receptor on these cells results in the development of a heterologous form of desensitization to agents which function to activate adenylate cyclase [Kelly, Keen, Nobbs & MacDermot (1990) Br. J. Pharmacol. 99, 306-316]. Agonist regulation of Gs alpha levels in these cells may contribute to this process.

Adenylyl Cyclases↗
PubMed1992

Gi3 does not contribute to the inhibition of adenylate cyclase when stimulation of an alpha 2-adrenergic receptor causes activation of both Gi2 and Gi3.

Agonist occupancy of the alpha 2-C10 adrenergic receptor in a stable clone (1C) of Rat 1 fibroblasts produced by transfection of cells with genomic DNA encoding this receptor causes the activation of both of the pertussis-toxin-sensitive G-proteins Gi2 and Gi3 [Milligan, Carr, Gould, Mullaney & Lavan (1991) J. Biol. Chem. 266, 6447-6455]. An IgG fraction from an antiserum (I3B) which identifies the C-terminal decapeptide of Gi3 alpha only was able to inhibit partially receptor stimulation of high-affinity GTPase activity. An equivalent fraction from an antiserum (AS7) able to identify the C-terminal decapeptide of Gi1 alpha + Gi2 alpha, but not Gi3 alpha, was also able to inhibit partially receptor stimulation of GTPase activity, and the effects of the two antisera were additive. By contrast, agonist-mediated inhibition of forskolin-amplified adenylate cyclase activity was abolished completely by the IgG fraction of antiserum AS7, but was not decreased by treatment with antiserum 13B. Based on the proportion of agonist-stimulated high-affinity GTPase which was prevented by each antiserum and on the measured membrane levels of Gi2 and Gi3, calculations indicated that essentially all of the cellular Gi3, but only 15% of the available Gi2, can be activated by the alpha 2-C10 adrenergic receptor in these cells. These results demonstrate that, although Gi3 is activated by alpha 2-adrenergic agonists in membranes of clone 1C cells, it does not contribute to the transduction of receptor-mediated inhibition of adenylate cyclase.

Adenylyl Cyclase Inhibitors↗
PubMed1992

Regulation of cardiac adenylate cyclase activity in rodent models of obesity.

We have investigated beta-adrenergic regulation of adenylate cyclase activity in heart tissue membranes from the genetically obese Zucker rat, the genetically obese CBA mouse and the genetically obese diabetic (db/db) mouse. Responsiveness to beta-adrenergic stimulation was impaired in membranes from the obese Zucker rat, but not in the other models. The membranes from obese Zucker rats showed both decreased beta-adrenergic-receptor number and altered coupling between beta-adrenergic receptors and the stimulatory guanine-nucleotide-binding protein, Gs. In contrast, no alterations in either the levels of Gs or the functional interaction between this protein and the catalytic moiety of adenylate cyclase were observed. In these three genetic models of obesity we observe dissimilar alterations in the control of adenylate cyclase.

Adenylyl Cyclases↗
PubMed1992

Gi down-regulation as a mechanism for heterologous desensitization in adipocytes.

Prolonged incubation of rat adipocytes with (-)N6-phenylisopropyl adenosine (PIA) (an A1 adenosine receptor agonist) leads to down-regulation of each of the three subtypes of Gi (Green, A., Johnson, J. L., and Milligan, G. (1990) J. Biol. Chem. 265, 5206-5210). To determine whether other inhibitors of adenylylcyclase would have similar actions, we incubated adipocytes in primary culture with PIA, prostaglandin E1 (PGE1), or nicotinic acid. After various times cells were homogenized, and crude membrane fractions were analyzed on Western blots using antipeptide antisera to alpha- and beta-subunits of G-proteins (SG1 (which binds to alpha i1 and alpha i2), I3B (which binds to alpha i3), BN2 (binds to beta-subunits) and CS1 (recognizes forms of alpha s)). PIA and PGE1 caused approximately 90% down-regulation of alpha i1 and alpha i3, and about 50% loss of alpha i2 and beta-subunits. In contrast, nicotinic acid at concentrations up to 1 mM had no effect on levels of any of these Gi subtypes. None of the compounds altered levels of either a 43- or 47-kDa form of alpha s. PIA caused about a 50% decrease in binding of [3H]DPCPX (an A1 adenosine receptor antagonist), indicating adenosine receptor down-regulation; however, neither PGE1 nor nicotinic acid treatment altered [3H]DPCPX binding. None of the treatments affected the activity of adenylylcyclase when measured in the presence of 100 microM forskolin and 10 mM Mn2+, indicating that the catalytic subunit of adenylylcyclase is not altered. To determine whether Gi down-regulation results in heterologous desensitization, we incubated adipocytes with maximally effective concentrations of PIA (300 nM), PGE1 (3 microM), or nicotinic acid (1 mM) for 4 days. The cells were then washed and incubated for an additional 30 min with various concentrations of these compounds to determine their ability to inhibit lipolysis. PIA caused a (marked) decrease in the sensitivity of the cells to both PIA and PGE1, thus indicating heterologous desensitization. Similarly, PGE1 decreased the sensitivity of the cells to both PGE1 and PIA, again demonstrating heterologous desensitization. In contrast, prolonged incubation with nicotinic acid decreased the sensitivity of the cells to nicotinic acid but had no effect on the sensitivity of the cells to PIA. Adenylylcyclase in membranes from PGE1-treated cells showed decreased sensitivity to inhibition by PIA. In contrast, adenylylcyclase showed normal sensitivity to PIA in membranes from nicotinic acid-treated cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylyl Cyclases↗
PubMed1992

Alpha 2-C10 adrenergic receptors expressed in rat 1 fibroblasts can regulate both adenylylcyclase and phospholipase D-mediated hydrolysis of phosphatidylcholine by interacting with pertussis toxin-sensitive guanine nucleotide-binding proteins.

The alpha 2-C10 adrenergic receptor from human platelets was expressed permanently in Rat-1 fibroblasts. A series of clones that varied in expression of the receptor from 0 to 3.5 pmol/mg of membrane protein were isolated. We have demonstrated recently in cells of one of these clones (1C) that the alpha 2-C10 receptor interacts directly with two distinct pertussis toxin-sensitive G-proteins, Gi2 and Gi3 (Milligan, G., Carr, C., Gould, G. W., Mullaney, I., and Lavan, B.E. (1991) J. Biol. Chem. 266, 6447-6455). High affinity GTPase activity in membranes of cells from the various clones was stimulated by the addition of the alpha 2-adrenergic agonist UK14304, defining that the receptor coupled productively to the G-protein signaling system. Maximal stimulation of high affinity GTPase activity correlated with the levels of receptor expressed. Clones expressing the receptor also demonstrated agonist-mediated inhibition of adenylylcyclase. Futhermore, the alpha 2-C10 receptor in one clone (1C), but not other clones, promoted a marked stimulation in the generation of water-soluble products derived from phosphatidylcholine. The concentration of UK14304 required to produce half-maximal regulation of GTPase activity (20-30 nM), of forskolin-amplified adenylylcyclase activity (30-40 nM), and of choline generation (30-40 nM) were similar. Transphosphatidylation experiments with cells of clone 1C indicated that the receptor-mediated hydrolysis of phosphatidylcholine was via the action of a phospholipase D. All of these effects were attenuated by pretreatment of the cells with pertussis toxin. Dose-effect curves of pertussis toxin-treatment demonstrated similar effective concentrations of the toxin in causing endogenous ADP-ribosylation of both Gi2 and Gi3, inhibition of receptor-stimulated GTPase activity, and phospholipase D activity. Receptor activation of phospholipase D activity was not dependent upon prior phospholipase C-dependent activation of protein kinase C, as alpha 2-adrenergic stimulation of inositol phosphate production was negligible and the presence of the selective protein kinase C inhibitor RO-31-8220, at concentrations up to 10 microM, had no effect on UK14304-mediated production of phosphatidylbutanol. These results demonstrate that expression of the alpha 2-C10 receptor in a heterologous system can result in receptor regulation of signaling elements that appear not to be primary targets for the receptor in vivo. Such results are important in respect to recent observations that transfection of a single defined receptor into separate cell lines can lead to the regulation of distinct effector systems (Vallar, L., Muca, C., Magni, M., Albert, P., Bunzow, J., Meldolesi, J. and Civelli, O. (1990) J. Biol. Chem. 265, 10320-10326).(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate Ribose↗
PubMed1992

Immunological identification of the alpha subunit of G13, a novel guanine nucleotide binding protein.

An antiserum (13CB) was generated against a synthetic peptide, HDNLKQLMLQ, which is predicted to represent the C-terminal decapeptide of the alpha subunit of the novel G-protein, G13. Competitive ELISA indicated that the antiserum reacted with this peptide but that it showed minimal ability to recognize peptides which represent the equivalent regions of the pertussis toxin-insensitive G-proteins, Gq + G11, G12, G15 + G16, GL1 (also called G14) as Gz, and well as other G-proteins. Immunoblots of human platelet membranes with antiserum 13CB identified a single 43-kDa polypeptide, and while this immunoreactivity was abolished by the presence of the cognate peptide it was not modified by the presence of peptides corresponding to the equivalent region of other G-proteins. Immunoreactivity corresponding to G13 alpha was detected in a range of cell types with human platelets having the highest levels of this polypeptide.

Amino Acid Sequence↗
PubMed1992

Treatment with triiodothyronine decreases the abundance of the alpha-subunits of Gi1 and Gi2 in the cerebral cortex.

Treatment of rats for 3 days with T3 halved the abundance of the alpha-subunits of Gi1 and Gi2 in synaptosomal membranes isolated from the cerebral cortex. It is suggested that these changes could contribute to behavioural abnormalities in hyperthyroidism. Similar T3 treatment did not alter abundance of Gi1 alpha or Gi2 alpha in the medulla oblongata nor did it alter abundance of G(o) alpha-subunits in three tested brain regions.

Amino Acid Sequence↗
PubMed1992

Immunohistochemical distribution of neurons containing the G-proteins Gq alpha/G11 alpha in the adult rat brain.

A new class of G-proteins, the Gq family, has been recently identified and found to be involved in phospholipase C activation. The alpha subunits of the Gq and G11 members of this family are separate polypeptides but appear to have the same function. In this study, the cellular distribution in the adult rat brain of these G-proteins, Gq alpha/G11 alpha, was determined by immunohistochemistry using an antipeptide antiserum directed against the predicted C-terminal decapeptide which is conserved between these polypeptides. The specificity of the antiserum was verified by Western blot analysis using rat brain homogenates. Immunoreactivity was detected in neurons, where it was localized in the dendrites and at the periphery of the cell bodies. The staining was abundant in the dendrites of cerebellar Purkinje cells and hippocampal CA1 pyramidal cells. Staining was also found in neurons in the olfactory bulb, minor and major islets of Calleja, anterior olfactory nuclei and piriform cortex; the different cortical areas especially in their superficial layers; caudate-putamen, accumbens and olfactory tubercle; lateral septum and amygdala; hippocampal CA2-4 sectors of Ammon's horn, dentate gyrus and hilus; hypothalamic supraoptic nucleus; cerebellar granular layer; colliculi and superficial layers of the dorsal horn of the spinal cord. In conclusion, the brain neuronal localizations of Gq alpha/G11 alpha match that of phospholipase C, 1,4,5-triphosphate receptor and, to a lesser extent 1,4,5-triphosphate-3-kinase.

Animals↗
PubMed1992

Radiographic patterns and associations of osteoarthritis of the hip.

A number of patterns of osteoarthritis of the hip are described, though studies are conflicting with respect to the frequency of such patterns and their associations. Two hundred and eleven patients (133 women, 78 men; mean age 66 years, range 29-86) referred to hospital with osteoarthritis of the hip were studied. Involvement was unilateral in 108 (51%) and bilateral in 89 (42%); 14 (7%) had undergone arthroplasty and were presenting with osteoarthritis hips). Sixty one per cent of hips had severe, 28% moderate, and 11% mild changes (Kellgren grade). Superior pole migration occurred in 82% (46% superolateral, 25% intermediate, 11% superomedial), medial/axial migration occurred in only 8%, and in 10% the pattern was indeterminate. In bilateral osteoarthritis of the hip the pattern was generally symmetrical. Superomedial and medial/axial patterns were proportionately more common in women, whereas superlateral osteoarthritis predominated in men. No association was found between multiple clinical nodes, radiographic polyarticular interphalangeal or first carpometacarpal osteoarthritis and any migration pattern. Any interphalangeal osteoarthritis was negatively associated with medial migration. Only 40% of hips could be categorised as hypertrophic or atrophic; chondrocalcinosis at any site was associated with atrophic osteoarthritis; no associations were seen with Forestier's disease. This large survey confirms the association between chondrocalcinosis and atrophic osteoarthritis of the hip. Importantly it suggests that gender, rather than associated osteoarthritis at other sites, is a major determinant of the pattern of osteoarthritis of the hip.

Adult↗
PubMed1992

Immunological characterization of the guanine-nucleotide binding proteins Gi and Go in rat islets of Langerhans.

Inhibition of insulin secretion from rat islets of Langerhans is known to involve at least one pertussis toxin-sensitive guanine-nucleotide binding (G) protein. We have used antisera raised against unique antigenic determinants of different members of the family of pertussis toxin-sensitive G proteins to identify these proteins in rat islets. Antiserum SG1, which recognizes both Gi1 and Gi2, reacted with an islet protein having an approximate Mr of 40,000. Antiserum I1C (Gi1 specific) failed to recognize any islet proteins, suggesting that Gi2 is present in much greater amounts than Gi1. Indeed, Gi1 levels were below the detection limit of a sensitive immunogold/silver-staining method, indicating that it may be absent from the cells of rat islets. Two different antisera were used to identify Go-like G proteins in rat islet homogenates. Both antisera reacted with a protein band which, under appropriate conditions, could be resolved to reveal two separate proteins of Mr 39-40,000. Thus, at least two molecular forms of Go are present in rat islets. Subcellular fractionation indicated that all three G proteins identified in this study (Gi2 and two forms of Go) are localized to islet membranes. No immunoreactivity could be detected in the cytosolic fraction.

Amino Acid Sequence↗