The association between personality disorder and an act of deliberate self harm in the older person.

BACKGROUND: Suicide rates are higher in the over 65s than in younger adults and there is a strong link between deliberate self harm (DSH) and suicide in older people. The association between personality disorder (PD) and DSH in older adults remains uncertain. Our objective was to describe this association. METHODS: A case control study was conducted in which participants were: (i) those who had undertaken an act of DSH and (ii) a hospital-based control group drawn from a geographical contiguous population. PD was assessed using the Standardised Assessment of Personality (SAP). RESULTS: Seventy-seven cases of DSH were identified; 61 (79.2%) of these participants were interviewed. There were 171 potential controls identified of whom 140 (81.9%) were included. An SAP was completed in 45/61 (73.8%) of cases and 100/140 (71.4%) of controls. The mean age was 79.8 years (SD = 9, range 65-103). The crude odds ratio for the association between PD and DSH was 5.91 [(95% CI 2.3, 14.9) p<0.0001]. There was a strong interaction with age stratified at 80 years. There was no association between PD and DSH after age 80. The adjusted odds ratio for PD in the group <80 years was 20.5 [(95% CI 3, 141) p = 0.002]. Borderline and impulsive PD traits tended to be associated with an episode of DSH more than other personality types. CONCLUSIONS: PD appears to be a strong and independent risk for an act of DSH in people aged between 65 and 80 years and should be looked for as part of any risk assessment in this population. Access to specialist services may be required to optimally manage this problem and reduce the subsequent risk of suicide.

Mucociliary clearance in COPD can be increased by both a D2/beta2 and a standard beta2 agonists.

In addition to breathlessness and cough, excessive mucus production is one of the main symptoms of chronic obstructive pulmonary disease (COPD). Excess mucus coupled with deteriorating mucociliary clearance is associated with a decline in lung function and an increased risk of death from pulmonary infection. The effect of Viozan (Sibenadet HCl, AR-C68397AA), a novel dual D2 dopamine receptor, beta2-adrenoceptor agonist, on mucociliary clearance was investigated together with that of a beta2-adrenoceptor agonist, salbutamol. Using a double blind, parallel group study design, 15 patients with COPD, all habitual smokers, were randomised to receive nebulised sidenadet (3mg tid; n = 7) or salbutamol (5mg tid; n = 8) for 10 days. Lung mucociliary clearance rates were measured, by a standard radioaerosol technique, before and after the treatment period, as were 24-h sputum volumes. Both sibenadet and salbutamol therapies resulted in significant (P<0.02) enhancement of lung mucociliary clearance. The 24-h sputum volume was significantly reduced following sibenadet therapy (P<0.03) whereas salbutamol therapy had no effect. Our results, in addition to illustrating the effects of a standard beta2 agonist on mucociliary clearance, strongly suggest the potential dual benefit of dual-agonist compounds in lessening sputum production whilst simultaneously enhancing mucociliary clearance. For reasons unconnected with the present study, development work on this specific formulation is no Longer proceeding.

High copy arrays containing a sequence upstream of mec-3 alter cell migration and axonal morphology in C. elegans.

BACKGROUND: The Caenorhabditis elegans gene mec-3 encodes a LIM-homeodomain protein that is a master regulator of touch receptor neuron genes. Two of the touch neurons, the ALM neurons, are generated in the anterior of the animal and then migrate to near the middle of the animal. In animals transformed with a sequence upstream of mec-3, the ALM touch receptor neurons failed to migrate to their normal positions and sometimes migrated in the wrong direction, and the PLM touch receptor neurons showed axonal defects. Here we characterize this effect and identify the sequence causing the cell migration and axonal defects. RESULTS: The ALM migration defect did not result from RNA interference (RNAi), nonspecific effects of carrying a transgenic array, expression of GFP, or the marker gene used to make the transformants. Instead, the ALM migration defect resulted from transgenic arrays containing many copies of a specific 104 bp DNA sequence. Transgenic arrays containing this sequence did not affect all cell migrations. CONCLUSIONS: The mec-3 upstream sequence appeared to be sequestering (titrating out) a specific DNA-binding factor that is required for the ALMs to migrate correctly. Because titration of this factor could reverse the direction of ALM migrations, it may be part of a program that specifies both the direction and extent of ALM migrations. mec-3 is a master regulator of touch receptor neuron genes, so the factor or factors that bind this sequence may also be involved in specifying the fate of touch receptor neurons.

Botulinum toxin injection for spasmodic torticollis: increased magnitude of benefit with electromyographic assistance.

To determine the usefulness of EMG-assisted botulinum toxin (BOTOX) injections for the treatment of spasmodic torticollis (ST), we randomized 52 ST patients into two groups and studied them prospectively. In one group [(E+C)RX, N = 28], the muscles were selected for BOTOX injection using both clinical and EMG examination and then injected with EMG assistance. In the second group [(C)RX, N = 24] the muscles were selected for BOTOX injection based solely on clinical examination and injected without EMG assistance. The percentage of patients showing any improvement after BOTOX as similar in both the (E+C)RX and (C)RX groups. A significantly greater magnitude of improvement was present in the (E+C)RX group, as well as a significantly greater number of patients with marked improvement. In particular, patients with retrocollis, head tilt, and shoulder elevation demonstrated additional benefit with EMG-assisted BOTOX injection. EMG assistance may be effective because the technique increases the ability to effectively identify and treat the deep cervical muscles.

Physical therapy and Parkinson's disease: a controlled clinical trial.

In a randomized, single-blind, crossover study, we evaluated physical disability in moderately advanced Parkinson's disease (PD) patients after 4 weeks of normal physical activity and 4 weeks of an intensive physical rehabilitation program. We used a timed motor task and a standard assessment of PD severity (the Unified Parkinson's Disease Rating Scale [UPDRS] with subscales for mentation, activities of daily living [ADL], and motor function) completed by an investigator blinded to the physical rehabilitation status of the patient. Following physical rehabilitation, there was significant improvement in the UPDRS ADL and motor scores, but no change in mentation score. During the 6 months following physical rehabilitation, patients did not regularly exercise, and the UPDRS scores returned to baseline. We conclude that physical disability in moderately advanced PD objectively improves with a regular physical rehabilitation program, but this improvement is not sustained when normal activity is resumed.

Group 1 mGlu receptors elevate [Ca2+]i in rat cultured cortical type 2 astrocytes: [Ca2+]i synergy with adenosine A1 receptors.

Brain macroglia are known to express a diverse array of neurotransmitter receptors whose signal transduction pathways may be subject to heteroreceptor 'cross-talk'. In the current study we have examined group 1 mGlu receptor-evoked [Ca2+]i signalling, and possible heteroreceptor cross-talk, in cultured type 2 astrocytes. The selective group 1 metabotropic glutamate (mGlu) receptor agonist (S)-3,5-dihydroxyphenylglycine (DHPG) elevated [Ca2+]i (EC50 = 1.7 +/- 0.6 microM); an effect reversed by the selective mGlu receptor antagonist (S)-alpha-methyl-4-carboxyphenylglycine (IC50 = 52.7 +/- 8.7 microM). DHPG-evoked [Ca2+]i responses were abolished by (1) thapsigargin (100 nM), implicating the involvement of internal Ca2+ stores in group 1 mGlu [Ca2+]i responses and (2) the removal of extracellular Ca2+. When applied alone, the selective adenosine A1 receptor agonist, N6-cyclopentyladenosine (CPA, 100 nM) failed to influence [Ca2+]i. However, in the presence of 1 microM DHPG, CPA potently (EC50 = 12.3 +/- 1.9 nM) increased [Ca2+]i responses. In the presence of 100 nM CPA, the efficacy of DHPG was doubled without any significant change in the DHPG EC50 value. This effect was reversed by either the selective adenosine A1 receptor antagonist, 8-cyclopentyltheophylline (IC50 = 50.3 +/- 19.9 nM) or overnight incubation with Pertussis toxin (100 ng/ml). We conclude that (1) type 2 astrocytes contain group 1 mGlu receptors coupled to [Ca2+]i signalling and (2) co-activation of adenosine A1 receptors enhances group 1 mGlu-evoked [Ca2+]i responses in these cells via a Gi/o G protein-mediated mechanism.

Inhibition of AMPA receptor-stimulated 57Co2+ influx by D- and L-2-amino-4-phosphonobutanoic acid (D- and L-AP4) and L-serine-O-phosphate (L-SOP) in cultured cerebellar granule cells.

This study describes the inhibition of 57Co2+ influx through Ca2+-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, consequent to the application of L-2-amino-4-phosphonobutanoic acid (L-AP4), D-AP4 and L-serine-O-phosphate (L-SOP) in cultured cerebellar granule cells. The forskolin-stimulated accumulation of cyclic AMP was inhibited by (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (L-CCG-1) with an IC50 = 491 +/- 135 nM and by L-AP4 in a biphasic manner (IC50(1) = 232 +/- 61 nM and IC50(2) = >300 microM), confirming the presence of group II and group III mGlu receptors, respectively. 57Co2+ influx was stimulated by kainate (EC50 = 42.2 +/- 11.3 microM) and, in the presence of 30 microM cyclothiazide, by (S)-5-fluorowillardiine (EC50 = 0.7 +/- 0.1 microM) and (S)-AMPA (EC50 = 2.8 +/- 0.5 microM). The effects of the latter were abolished by 10 microM 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX). L-AP4 (IC50 = >300 microM), D-AP4 (IC50 = >100 microM) and L-SOP (IC50 = 199 +/- 6 microM) inhibited 6 microM (S)-AMPA-stimulated 57Co2+ influx, whereas L-CCG-1 (up to 10 microM), 300 microM (RS)-3,5-dihydroxyphenylglycine, 300 microM (+/-)-baclofen and 1 mM carbachol were ineffective. Pre-incubation with either pertussis toxin (250 ng/ml, 48 hr), 1 mM dibutyryl cyclic AMP, or the potent group III mGlu receptor antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine ((RS)-CPPG), tested at 400 microM, failed to alter the inhibition of AMPA receptor activity by 300 microM L-SOP. Unlike 10 microM NBQX, neither L-AP4, D-AP4 or L-SOP (tested at 1 mM) inhibited the binding of 10 nM (S)-[3H]5-fluorowillardiine (a selective AMPA receptor ligand) to granule cell membranes. Therefore, in these neurones, high concentrations (>100 microM) of L-AP4, L-SOP and D-AP4 inhibit Ca2+-permeable AMPA receptors by a mechanism distinct from known mGlu receptor action and at a site independent from that for AMPA receptor agonists.

A novel kainate receptor ligand [3H]-(2S,4R)-4-methylglutamate: pharmacological characterization in rabbit brain membranes.

Since kainate evokes large non-desensitizing currents at alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, kainate is of limited use in discriminating between AMPA and kainate receptors. Following recent reports that (2S,4R)-4-methylglutamate is a kainate receptor-selective agonist, we have radiolabelled and subsequently characterized the binding of [3H]-(2S,4R)-4-methylglutamate to rabbit whole-brain membranes. [3H]-(2S,4R)-4-methylglutamate binding was rapid, reversible and labelled two sites (KD1 = 3.67+/-0.50 nM/Bmax1 = 0.54+/-0.03 pmol/mg protein and KD2 = 281.66+/-12.33 nM/ Bmax2 = 1.77+/-0.09 pmol/mg protein). [3H]-(2S,4R)-4-methylglutamate binding was displaced by several non-NMDA receptor ligands: domoate > kainate >> L-quisqualate > or = L-glutamate > 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) >> (S)-AMPA = (S)-5-fluorowillardiine > NMDA. Neither the metabotropic glutamate receptor agonists (1S,3R)-ACPD or L-AP4, together with the L-glutamate uptake inhibitor L-trans-2,4-PDC, influenced binding when tested at 100 microM. We conclude that [3H]-(2S,4R)-4-methylglutamate is a useful radioligand for labelling kainate receptors. It possesses high selectivity, and possesses a pharmacology similar to that for rat cloned low-affinity (Glu5 and 6) kainate receptor subunits.

Functional coupling of rat metabotropic glutamate 1a receptors to phospholipase D in CHO cells: involvement of extracellular Ca2+, protein kinase C, tyrosine kinase and Rho-A.

We report here that metabotropic glutamate 1a (mGlu1a) receptors, stably expressed in CHO cells, stimulate phospholipase D (PLD) activity. Several mGlu receptor agonists were found to exert this effect, with a rank order of potency of: L-quisqualate>L-glutamate>(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid [(1S,3R)-ACPD]=(S)-3,5-dihydroxyphenylglycine [(S)-DHPG]. Both L-glutamate- and (1S,3R)-ACPD-stimulated PLD activity were attenuated by the selective mGlu receptor antagonist (S)-alpha-methyl-4-carboxyphenylglycine. mGlu1a receptor-stimulated PLD was inhibited either by the selective protein kinase C (PKC) inhibitor, GF109203X, or via PKC downregulation. MGlu1a receptor-PLD coupling required extracellular Ca2+ and was sensitive to La3+ and Zn2+, inhibitors of intracellular Ca2+ store-operated Ca2+ influx. mGlu1a receptor-PLD coupling was inhibited by the selective tyrosine kinase inhibitor, genistein. In addition, mGlu1a receptor-PLD coupling was also inhibited by cell transfection with the selective Rho (small GTP-binding protein) inhibitors: C3-exoenzyme and dominant negative mutant RhoA constructs. Brefeldin A, a selective ADP-ribosylation factor (ARF) inhibitor, and a dominant negative ARF6 mutant, failed to significantly influence mGlu1a receptor-stimulated PLD activity. We conclude that mGlu1a receptors activate PLD via a mechanism that is dependent on extracellular Ca2+, PKC, tyrosine kinase and RhoA but independent of ARF.

Group I mGlu receptors potentiate synaptosomal [3H]glutamate release independently of exogenously applied arachidonic acid.

In the current study, we have characterized group I metabotropic glutamate (mGlu) receptor enhancement of 4-aminopyridine (4AP)-evoked [3H]glutamate release from rat cerebrocortical synaptosomes. The broad spectrum mGlu receptor agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD, 10 microM) increased 4AP-evoked [3H]glutamate release (143.32+/-2.73% control) only in the presence of exogenously applied arachidonic acid; an effect reversed by the inclusion of bovine serum albumin (BSA, fatty acid free). In contrast, the selective group I mGlu receptor agonist (S)-3,5-dihydroxyphenylglycine (DHPG) potentiated (EC50 = 1.60+/-0.25 microM; Emax = 147.61+/-10.96% control) 4AP-evoked [3H]glutamate release, in the absence of arachidonic acid. This potentiation could be abolished by either the selective mGlu1 receptor antagonist (R,S)-1-aminoindan-1,5-dicarboxylic acid (AIDA, 1 mM) or the selective PKC inhibitor (Ro 31-8220, 10 microM) and was BSA-insensitive. The selective mGlu5 receptor agonist (R,S)-2-chloro-5-hydroxyphenylglycine (CHPG, 300 microM) was without effect. DHPG (100 microM) also potentiated both 30 mM and 50 mM K+ -evoked [3H]glutamate release (121.60+/-12.77% and 121.50 +/-4.45% control, respectively). DHPG (100 microM) failed to influence both 4AP-stimulated 45Ca2+ influx and 50 mM K+ -induced changes in synaptosomal membrane potential. Possible group I mGlu receptor suppression of tonic adenosine A1 receptor, group II/III mGlu receptors or GABA(B) receptor activity is unlikely since 4AP-evoked [3H]glutamate release was insensitive to the selective inhibitory receptor antagonists 8-cyclopentyl-1,3-dimethylxanthine, (R,S)-alpha-cyclopropyl-4-phosphonophenylglycine or CGP55845A, respectively. These data suggest an 'mGlu1 receptor-like' receptor potentiates [3H]glutamate release from cerebrocortical synaptosomes in the absence of exogenously applied arachidonic acid. This PKC dependent effect is unlikely to be via modulation of synaptosomal membrane potential or voltage-activated Ca2+ channels and not via a suppression of tonically active inhibitory adenosine A1 receptor, group II/III mGlu receptors or GABA(B) receptors.

The effects of (RS)-alpha-cyclopropyl-4-phosphonophenylglycine ((RS)-CPPG), a potent and selective metabotropic glutamate receptor antagonist.

1. In this study we describe the potent antagonist activity of a novel metabotropic glutamate (mGlu) receptor antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine ((RS)-CPPG) which exhibits selectivity for mGlu receptors (group II and III) negatively coupled to adenylyl cyclase in the adult rat cortex. 2. Both the L-2-amino-4-phosphonobutyrate (L-AP4) and (2S, 1'S, 2'S)-2-(carboxycyclopropyl)glycine (L-CCG-1) inhibition of forskolin-stimulated cyclic AMP accumulation were potently reversed by (RS)-CPPG (IC50 values: 2.2 +/- 0.6 nM and 46.2 +/- 18.2 nM, respectively). 3. In contrast, (RS)-CPPG acted as a weak antagonist against group I mGlu receptors. In neonatal rat cortical slices, (RS)-CPPG antagonized (KB = 0.65 +/- 0.07 mM) (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD)-stimulated phosphoinositide hydrolysis. (RS)-CPPG (100 microM) failed to influence L-quisqualate-stimulated phosphoinositide hydrolysis in cultured cerebellar granule cells. 4. In the rat cerebral cortex, (RS)-CPPG is the most potent antagonist of group II/III mGlu receptors yet described (with 20 fold selectivity for group III mGlu receptors), having negligible activity at group I mGlu receptors.

Characterization of metabotropic glutamate receptor-stimulated phosphoinositide hydrolysis in rat cultured cerebellar granule cells.

1. The pharmacology of excitatory amino acid (EAA)-stimulated phosphoinositide (PI) hydrolysis, monitored via [3H]-inositol monophosphate accumulation, was investigated in primary cultures of rat cerebellar granule cells. 2. EAA-stimulated PI hydrolysis peaked after 4-5 days in vitro and subsequently declined. 3. The agonist order of potency was found to be (EC50): L-quisqualic acid (Quis) (2 microM) >> L-glutamate (50 microM) > (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD) (102 microM). L-Glutamate (Emax = 873% of basal activity) elicited the largest stimulation of PI hydrolysis, whereas Quis (Emax = 603%) and (1S,3R)-ACPD (Emax = 306%) produced somewhat lower stimulations. 4. Several phenylglycine derivatives were found to be active in inhibiting 2 microM Quis-stimulated PI hydrolysis, in order of potency (IC50): (S)-4-carboxy-3-hydroxyphenylglycine (41 microM) > or = (S)-4-carboxyphenylglycine (51 microM) >> (+)-alpha-methyl-4-carboxyphenylglycine (243 microM). 5. Cultured cerebellar granule cells of the rat appear to have Group I mGluR pharmacology similar to that reported for cloned mGluR1 and provide an ideal system for investigating novel mGluR1 ligands in a native environment.

NMDA receptor-mediated stimulation of rat cerebellar nitric oxide formation is modulated by cyclic AMP.

The effect of intracellular cyclic AMP (cAMP) on N-methyl-D-aspartate (NMDA) receptor-mediated stimulation of nitric oxide (NO) formation was investigated in rat cerebellar slices. Forskolin (30-120 microM), while lacking any direct effect on NO production, elicited a concentration-dependent enhancement of the response to 10 microM NMDA. Dideoxyforskolin, which does not activate adenylyl cyclase did not influence the NMDA response. Increasing intracellular cAMP directly by incubation with the membrane-permeant analogue of cAMP, 2'-o-dibutyryladenosine 3'5'-cyclic monophosphate (dibutyryl cAMP) (1 mM), similarly enhanced NO formation, as did prevention of cAMP degradation with the phosphodiesterase inhibitor theophylline. The enhancement of NMDA activity appeared to involve protein phosphorylation (possibly of the receptor itself) since the protein kinase A inhibitor H-89, abolished the enhancements with both forskolin and dibutyryl cAMP. Thus cAMP may have a physiological role in the modulation of NMDA receptor-stimulated synthesis of NO.

Group I metabotropic glutamate receptors limit AMPA receptor-mediated oligodendrocyte progenitor cell death.

Oligodendrocyte progenitor cells were found to be vulnerable to kainate excitotoxic insults, an effect inhibited by either the selective alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist (1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (GYKI 52466)) or the selective group I metabotropic glutamate (mGlu) receptor agonist, (S)-3,5-dihydroxyphenylglycine. The protective effects of (S)-3,5-dihydroxyphenylglycine were reversed by the selective mGlu receptor antagonist, (S)-alpha-methyl-4-carboxyphenylglycine. These data suggest that group I mGlu receptors may limit oligodendrocyte progenitor cell degeneration during acute brain insults.

Novel potent selective phenylglycine antagonists of metabotropic glutamate receptors.

The metabotropic glutamate (mGlu) receptor antagonist properties of novel phenylglycine analogues were investigated in adult rat cortical slices (mGlu receptors negatively coupled to adenylyl cyclase), neonatal rat cortical slices and in cultured rat cerebellar granule cells (mGlu receptors coupled to phosphoinositide hydrolysis). (RS)-alpha-methyl-4-phosphonophenylglycine (MPPG), (RS)-alpha-methyl-4-sulphonophenylglycine (MSPG), (RS)-alpha-methyl-4-tetrazolylphenylglycine (MTPG), (RS)-alpha-methyl-3-carboxymethyl-4-hydroxyphenylglycine (M3CM4HPG) and (RS)-alpha-methyl-4-hydroxy-3-phosphonomethylphenylglycine (M4H3PMPG) were demonstrated to have potent and selective effects against 10 microM L-2-amino-4-phosphonobutyrate (L-AP4)- and 0.3 microM (2S,1'S,2'S)-2-(2-carboxycyclopropyl)glycine (L-CCG-1)-mediated inhibition of forskolin-stimulated cAMP accumulation in the adult rat cortex. In contrast, these compounds demonstrated either weak or no antagonism at mGlu receptors coupled to phosphoinositide hydrolysis in either neonatal rat cortex or in cultured cerebellar granule cells. These compounds thus appear to be useful discriminatory pharmacological tools for mGlu receptors and form the basis for the further development of novel antagonists.

Regional mapping of low-affinity kainate receptors in mouse brain using [(3)H](2S,4R)-4-methylglutamate autoradiography.

Recent data indicate that (2S,4R)-4-methylglutamate is a selective agonist for low affinity (GluR5 and GluR6) kainate receptor subunits. In the present study, we have employed [(3)H](2S,4R)-4-methylglutamate to examine low affinity kainate receptor distribution in mouse brain. [(3)H](2S,4R)-4-Methylglutamate labelled a single site in murine cerebrocortical membranes (K(d)=9.9+/-2.7 nM, B(max)=296.3+/-27.1 fmol mg protein(-1)). The binding of 8 nM [(3)H](2S,4R)-4-methylglutamate was displaced by several non-NMDA receptor ligands (K(i)+/-S.E.M.): domoate (1.1+/-0.2 nM)>kainate (7.1+/-1.1 nM) >> L-glutamate (187.6+/-31.9 nM) >> (S)-alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) (>50 microM). [(3)H](2S,4R)-4-Methylglutamate autoradiography revealed a widespread regional distribution of low affinity kainate receptors. Highest binding densities occurred within deep layers of the cerebral cortex, olfactory bulb, basolateral amygdala and hippocampal CA3 subregion. Moderate labelling was also evident in the nucleus accumbens, dentate gyrus, caudate putamen, hypothalamus and cerebellar granule cell layer. These data show that [(3)H](2S,4R)-4-methylglutamate is a useful radioligand for selectively labelling low affinity kainate receptors.

Effect of salmeterol xinafoate on lung mucociliary clearance in patients with asthma.

Lung mucociliary clearance is impaired in stable asthma. The long-acting beta2-agonist salmeterol has been shown in vitro to cause a significant increase in ciliary beat frequency. It seemed possible therefore that salmeterol may also have a favourable effect on lung mucociliary transport in asthmatic patients. Fourteen patients with asthma participated in a double-blind, placebo-controlled, crossover study to assess the effect of 2 weeks of treatment with salmeterol MDI (50 microg b.d.) on lung mucociliary clearance. The 11 patients who completed the study (seven males, four females) had a mean +/- SE age of 50 +/- 4 years, % predicted FEV1 of 74 +/- 8% and a tobacco consumption history of 13 +/- 7 pack-years (seven non-smokers, four exsmokers). Lung mucociliary transport was measured by a radioaerosol technique. Pulmonary function indices (FEV1, FVC, and PEF) were significantly improved on salmeterol relative to placebo. The main radioaerosol finding was a significant increase in the penetration of radioaerosol into the lung with 24-h radioaerosol rising from 40 +/- 5% on placebo to 49 +/- 4% (P < 0.01) on salmeterol. Despite this increased penetration, a slight favourable change occurred in tracheobronchial aerosol clearance. This study demonstrates that 2 weeks salmeterol treatment influences deposition of particles within the lung by increasing airway patency and indicates a beneficial effect of MDI salmeterol on lung mucociliary clearance.

Sodium nitroprusside-induced rat fundus relaxation is ryanodine-sensitive and involves L-type Ca2+ channel and small conductance Ca(2+)-sensitive K+ channel components.

1 The aim of this study was to examine whether sodium nitroprusside (SNP)-induced relaxation of rat fundus longitudinal smooth muscle involves ryanodine-sensitive Ca2+ release. 2 SNP (300 nM-30 microM) elicited concentration-dependent relaxation of precontracted (1 microM carbachol) rat fundus, an effect almost abolished by the selective guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, 10 microM). 3 SNP-mediated relaxations were almost abolished by 10 microM ryanodine. 4 SNP-mediated relaxations were also reduced by either 1 microM apamin (a selective small conductance Ca(2+)-sensitive K+ channel, SKCa, inhibitor) or the selective L-type Ca2+ channel inhibitor, nicardipine (3 microM). 5 SNP-induced relaxations were insensitive to 1 mM tetraethylammonium chloride (an inhibitor of large-conductance Ca(2+)-sensitive K+ channels) and 1 microM glibenclamide (an ATP-sensitive K+ channel inhibitor). 6 These data suggest that SNP-mediated fundus relaxation occurs via a cGMP-mediated and ryanodine-sensitive mechanism which requires, at least in part, SKCa and L-type Ca2+ channel activity.