Investigation of the neurogenic bladder.
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Algorithms↗
Biomedical subjects
C J Fowler
Publications and source records attributed to C J Fowler.
Further validation of a simple biochemical method for evaluation of local anesthetic effects at sodium channels.
We previously reported that blockade of the phosphoinositide breakdown response to the sodium channel agonist veratrine provides a simple measure of local anesthetic actions at sodium channels. For such a model to be considered useful, it should show specificity for compounds whose primary actions are not upon sodium channels, but which have local anesthetic properties at high concentrations. In addition, it should be able appropriately to distinguish local anesthetic enantiomers. Such results were found in the present study. Thus, (-)-propranolol inhibited the phosphoinositide breakdown response to veratrine with an IC50 value of -20 microM, whereas the response to the sodium ionophore monensin was not affected. With respect to local anesthetic enantiomers, (S)-RAC-109 was 4-fold more potent than the (R)-enantiomer, IC50 values of -5 and -20 microM, respectively, being found. A considerable reduction in potency was, however, found when the side chain was lengthened by one carbon atom (IC50 for the racemate >100 microM). Such a pattern of activity is consistent with the literature, and further validates the use of blockade of veratrine-stimulated phosphoinositide breakdown as a simple biochemical measure of local anesthetic effects at sodium channels.
Anesthetics, Local↗
Diminished [3H]inositol(1,4,5)P3 but not [3H]inositol(1,3,4,5)P4 binding in Alzheimer's disease brain.
Levels of the calcium mobilising receptors for the phosphoinositide hydrolysis derived second messengers, inositol(1,4,5)trisphosphate [Ins(1,4,5)P3] and inositol(1,3,4,5) tetrakis-phosphate [Ins(1,3,4,5)P4] were compared in the cerebellum, superior temporal and superior frontal cortex of a series of Alzheimer's disease and matched control cases. Membrane [3H]Ins(1,4,5)P3 radioligand binding experiments performed under steady state conditions revealed that the number of Ins(1,4,5)P3 recognition sites was significantly decreased in all three brain regions of the Alzheimer's disease cases, compared to controls. In contrast, [3H]Ins(1,3,4,5)P4 binding levels, as assessed in competition analyses, were not significantly different between the groups in any brain region. Moreover, the Hill coefficients for inhibition of [3H]Ins(1,3,4,5)P4 binding by non-radioactive Ins(1,3,4,5)P4 were less than unity in both the control and Alzheimer's disease brains, suggesting that the heterogeneity of these binding sites are also maintained in the disease. It is concluded that disruptions of the phosphoinositide hydrolysis pathway in Alzheimer's disease brain are associated with a selective loss of calcium mobilising Ins(1,4,5)P3, but not Ins(1,3,4,5)P4 receptor sites. These alterations may contribute to an altered calcium homeostasis in Alzheimer's disease, as well as providing one reason for the lack of success of cholinergic replacement therapies aimed at enhancing muscarinic receptor-mediated phosphatidylinositol hydrolysis.
Aged↗
kappa-Opioid receptor recognition sites are not modulated by local anaesthetics.
Local anaesthetics and opioid drugs function synergistically to provide analgesia. In the present study, the nature of this synergy has been investigated using in vitro radioligand binding to determine whether the local anaesthetics bupivacaine and tetracaine modulate the binding of two kappa-opioid receptor ligands, [3H]U-69593 (5-alpha,7-alpha,8-beta-(-)-N-methyl-N[7-(1-pyrrolodinyl)-1-oxa spiro(4,5)dec-8-yl]-benzene acetamide) and [3H](-)-EKC (ethylketocyclazocine). [3H]U-69593 bound with a KD of 0.88 nM and a Bmax of 2.39 +/- 0.22 fmol/mg wet weight in guinea pig cerebellar membranes. The binding was inhibited by bremazocine and morphine with Hill slopes near unity and pI50 values of 9.96 and 6.84-6.86, respectively. [3H]U-69593 binding was inhibited by Gpp(NH)p (5'-guanylyl imidodiphosphate) and NaCl, consistent with an agonist action of the compound. The binding characteristics of the ligand were not changed by bupivacaine or tetracaine. [3H](-)-EKC bound with KD values of 0.55 and 0.97 nM and Bmax values of 4.22 and 0.99 fmol/mg wet weight in guinea pig cerebellar membranes and rat spinal cords, respectively. In the rat spinal cord, [3H](-)-EKC appeared to act as an agonist/antagonist, since the presence of Gpp(NH)p and NaCl only produced a small (21%) reduction in binding, but reduced the pI50 for the residual binding to inhibition by morphine from 6.33-6.39 to 5.95. As with [3H]U-69593, the binding characteristics of [3H](-)-EKC were not affected by bupivacaine or tetracaine. These studies demonstrate that effects of kappa-opioid receptor recognition site conformation are unlikely to explain the clinically observed synergy between local anaesthetics and opioids.
Anesthetics, Local↗
Preservation of kappa 1 opioid receptor recognition site density and regulation by G-proteins in the temporal cortex of patients with Alzheimer's disease.
The pharmacological properties of the kappa 1 opioid receptor were investigated in human post-mortem temporal cortical membranes from control and Alzheimer's disease brains, using the kappa 1-selective radioligand [3H]U69593. [3H]U69593 bound to a single high affinity site population with no significant difference between control (Bmax 31 +/- 4.14 fmol/mg protein, KD 1.01 +/- 0.26 nM) and Alzheimer's disease brains (Bmax 37 +/- 4.63 fmol/mg protein, KD 0.86 +/- 0.08 nM). Competition studies with dynorphin B and alpha-neoendorphin gave flat inhibition curves with Hill coefficients of 0.31 +/- 0.04 and 0.49 +/- 0.09 in the control brains and 0.38 +/- 0.05 and 0.48 +/- 0.08 in the Alzheimer's disease brains, respectively. The pI50 values for dynorphin B and alpha-neoendorphin were 8.73 +/- 0.17 and 8.48 +/- 0.09, respectively, in the control brains and 9.30 +/- 0.22 and 8.70 +/- 0.15 in the Alzheimer's disease brains. The guanine nucleotide analogue Gpp(NH)p inhibited binding by ca. 70% in both the control and Alzheimer's disease brains, the residual binding being sensitive to NaCl in both cases. These results indicate that the pharmacological properties and the functional integrity of G-protein coupling of the kappa 1 receptor recognition site are preserved in Alzheimer's disease temporal cortex.
Aged↗
Prevalence of bowel dysfunction in patients with multiple sclerosis and bladder dysfunction.
Urinary dysfunction is common in cases of multiple sclerosis (MS). The close proximity of those neural pathways which control the bladder to those which control anorectal function might be expected to lead to a high coexistence of bladder and bowel symptoms. Seventy-seven consecutive patients with clinically definite MS attending a uroneurology clinic were interviewed about their bowel function. All patients had clinical evidence of spinal cord disease with varying degrees of impaired mobility and sufficiently severe disturbance of bladder control to seek medical advice. Thirty-six per cent of these patients had constipation. Twenty per cent had "current incontinence", although another 30% had had at least one episode of faecal incontinence more than 3 months previously. Some patients had both constipation and faecal incontinence. A total of 52% currently had at least one bowel symptom. The pattern of bowel symptoms did not correlate with the pattern of urinary disturbance, or the duration of MS, or the degree of disability. Bowel symptoms are common in patients with MS, but even in those with urinary dysfunction are not universal. Whereas bladder dysfunction in MS is clearly related to spinal cord disease, the neurological basis for the bowel dysfunction is less clear.
Adult↗
Characteristics of [3H]inositol(1,3,4,5)tetrakisphosphate recognition sites in human cerebellar membranes.
The characteristics of specific [3H]Ins(1,3,4,5)P4 binding sites in human cerebellar membranes were determined in this study. Binding rapidly reached steady state, possessed a pH optimum of 4.5-5.1 and was greater in the absence of BSA than in its presence. Heparin inhibited both specific and pseudospecific binding of the ligand, whereas only the specific binding was inhibited by non-radioactive Ins(1,3,4,5)P4. Calcium at a concentration of 1 mM, reduced binding by 27%. Competition studies with other inositol phosphates showed specificity for Ins(1,3,4,5)P4 with a pI50 value of 6.87 and a Hill coefficient of 0.27, indicating two sites. Ins(1,2,5,6)P4, Ins(1,3,4,6)P5, Ins(3,4,5,6)P4 displaced binding with IC50 values ranging from 0.1-1 microM, Ins(1,2,5,6)P4 and Ins(1,3,4,5,6)P5 being the most potent. Ins(1,4)P2 and Ins(1,5,6)P3 had lesser effects on binding. Rosenthal analysis of [3H]Ins(1,3,4,5)P4 saturation binding data at low ligand concentrations gave a KD of 27 nM and a Bmax of 33 pmol/mg protein. It is concluded that [3H]Ins(1,3,4,5)P4 binding sites in human cerebellar membranes have similar characteristics to these sites reported in the literature in animal cerebellar tissue, but are in greater abundance.
Aged↗
Clinical value of the pudendal somatosensory evoked potential.
The pudendal evoked potential was recorded in 126 patients who had presented with various uro-genital complaints. The patients were divided into two groups depending on whether or not there were clinical signs of neurological disease. Group I consisted of 83 patients (66%) who on clinical examination were neurologically normal. In group II there were 43 patients (34%) who had physical signs suggesting underlying neurological pathology. The pudendal evoked potential was abnormal in 10 patients from the group with neurological signs (group II) but only 1 patient from group I (a man who had made an excellent recovery from previous transverse myelitis). The conclusion of this study is that the pudendal evoked potential is of no greater value than the clinical examination in the assessment of patients with uro-genital dysfunction. The recommendation that the potential should be recorded as part of the routine assessment of patients suspected of having a neurogenic disorder of the bladder and sexual function should be reconsidered.
Adolescent↗
Membrane alterations in Alzheimer's disease and aging.
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Aging↗
Pharmacological characterization of the N-methyl-D-aspartate (NMDA) receptor recognition site in porcine cerebral cortical membranes using [3H]-CGP 39653.
The high-affinity NMDA receptor competitive antagonist [3H]-CGP 39653 binds to Triton X-100 (0.04%) treated porcine cerebral cortex membranes in a saturable and reversible manner, with a KD of 6.1 +/- 0.97 nM and a Bmax of 944 +/- 55 fmol/mg protein. Association of ligand with the recognition site was rapid (estimated k1 = 1.1 x 10(7) M-1 min-1), and a steady state was reached within 30 min of incubation at 4 degrees C. Dissociation was also rapid (estimated k-1 = 0.2 min-1). The pharmacology of the binding site was similar to that for the rat brain, with mean pIC50 values (Hill slopes in parentheses, *indicating significant difference from unity) of 7.54 (0.51*), 6.99 (0.68*), 6.98 (0.71), 6.63 (0.80*), 6.31 (0.62*) and 5.17 (0.78) for R-CPP, L-glutamate, CGS 19755, cis-2,4-methanoglutamate, L-aspartate and NMDA, respectively. Other compounds (glycine, MK-801, kainate, S-AMPA and magnesium ions), previously observed not to interact competitively with the NMDA binding recognition site, showed a low affinity for the porcine cerebral cortex [3H]-CGP 39653 binding site. It is concluded that the pharmacological properties of the NMDA receptor recognition site labelled by [3H]-CGP 39653 are similar in the pig and rat cerebral cortices.
2-Amino-5-phosphonovalerate↗
Veratrine-stimulated phosphoinositide breakdown as an assay for local anesthetic actions at Na+ channels.
The blockade of veratrine-stimulated phosphoinositide breakdown in rat cerebral cortical miniprisms as a model of local anesthetic actions on voltage-dependent sodium channels was assessed. Veratrine stimulated phosphoinositide breakdown with an EC50 value of 5 microM. The stimulation produced by 20 microM veratrine was blocked completely by (+)-bupivacaine (IC50 7.6 microM [mean of three separate experimental series]), (-)-bupivacaine (IC50 7.3 microM), lidocaine (IC50 34 microM), etidocaine (IC50 3.4 microM), tetracaine (IC50 approximately 2 microM), and prilocaine (IC50 110 microM). Phosphoinositide breakdown responses to ouabain (100-1000 microM) and K+ (50 mM) were only partially blocked by (+)-bupivacaine, and the responses to monensin (100 and 1000 microM) and noradrenaline (30 microM) were not blocked at all by this drug. Nifedipine produced no significant effects on the phosphoinositide response to 10 microM veratrine. It is concluded that in pulse label experiments using rat cerebral cortical miniprisms, local anesthetics in general, and (+)-bupivacaine in particular, block the phosphoinositide response to veratrine with a high degree of specificity. This system may be useful as a relatively simple and quantitative assay for drug effects on Na(+)-channels.
Anesthetics, Local↗
Urethral sphincter volumes in women with obstructed voiding and abnormal sphincter electromyographic activity.
OBJECTIVE: To investigate the role of transrectal ultrasonography (TRUS) of the female urethral sphincter and to compare sphincter volumes in controls and women with obstructed voiding associated with abnormal myotonic-like electromyographic (EMG) activity in the urethral sphincter. PATIENTS AND METHODS: Fourteen women patients (mean age 29 +/- 3.2 years) with symptoms of urinary outlet obstruction underwent videocystometrography (VCMG), urethral sphincter EMG and TRUS. Their sphincter volumes were compared with those obtained from 20 age-matched control patients with other urodynamic diagnoses or normal urodynamics. RESULTS: In every patient the urethral sphincter was identified as an ovoid, hypoechoic structure distal to the bladder outlet. The mean volume of the sphincter in those patients with abnormal EMG activity (3.05 +/- 0.23 cm3) was significantly greater than that in the control group (1.30 +/- 0.09 cm3; P < 0.001). CONCLUSION: TRUS provided a useful method of imaging the urethral sphincter in women. The results suggest that there was an increase in the volume of the urethral sphincter in females with obstructed voiding, providing collateral evidence that the abnormal EMG activity is a significant factor in the pathophysiology of the disorder.
Adult↗
Nerve conduction studies, skeletal muscle EMG, and sphincter EMG in multiple system atrophy.
Although autonomic failure, parkinsonism, and cerebellar and pyramidal signs are well documented in multiple system atrophy, much less is known about the frequency and severity of involvement of the peripheral nervous system. The frequency and nature of peripheral nerve involvement has therefore been determined in 74 patients with multiple system atrophy using nerve conduction studies and skeletal muscle EMG. These findings were compared with those on sphincter EMG. Ninety per cent of the patients had an abnormal sphincter EMG, indicating denervation and reinnervation consistent with anterior horn cell loss in Onuf's nucleus, but only 40% had either abnormal nerve conduction studies (mixed sensorimotor axonal neuropathy in 17.5%) or abnormal skeletal muscle EMG (suggesting partial denervation in 22.5%). These data indicate a remarkable selective vulnerability of the anterior horn cells of Onuf's nucleus innervating external sphincter muscles relative to those supplying skeletal muscle in patients with multiple system atrophy. If this selective pattern of involvement can be explained it may be a clue to pathogenetic mechanisms in multiple system atrophy.
Adult↗
Regionally selective alterations in G protein subunit levels in the Alzheimer's disease brain.
In the present study the relative densities of a number of G protein subunits were quantified in membranes prepared from the hippocampus, temporal cortex and angular gyrus of Alzheimer's disease and control post-mortem brain by immunoblotting with specific polyclonal antisera against Gs alpha, Gi alpha, Gi alpha-1, G(o) alpha and G beta protein subunits. In addition, basal, Gs-stimulated and Gi-inhibited adenylyl cyclase activities were measured in the same hippocampal membrane samples. Densitometric analysis of the immunoblot data revealed a 58% reduction in the levels of Gi alpha, and a 75% reduction in the levels of Gi alpha-1, in the Alzheimer's disease temporal cortex. Gi alpha levels were reduced, by 37% in the angular gyrus of the Alzheimer's disease cases. The ratio of large to small molecular weight isoforms of the Gs alpha subunit was significantly increased in both the hippocampus and the angular gyrus of the Alzheimer's disease samples when compared to control values, although the difference in individual Gs alpha isoform levels did not attain statistical significance when comparing groups. No statistically significant differences were observed in G(o) alpha or G beta levels when comparing control and Alzheimer's disease cases. Gs-stimulated adenylyl cyclase activity was significantly reduced in the Alzheimer's disease samples compared to controls, whereas Gi-inhibited adenylyl cyclase activity was unchanged. No significant differences were observed between the control and Alzheimer's disease samples for either basal or forskolin stimulated adenylyl cyclase activity. The ratio of hippocampal Gs-stimulated to basal adenylyl cyclase activity correlated significantly with the large to small Gs alpha subunit ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenylyl Cyclases↗
Improved method for needle electromyography of the urethral sphincter in women.
Needle electromyography (EMG) of the urethral sphincter using the periurethral approach is a procedure which most women find painful and their discomfort can restrict the usefulness of the test. A new technique has been devised using a transvaginal approach. The patient lies in the left lateral position and using a Sims speculum the posterior vaginal wall is retracted. The urethral sphincter can be easily seen and palpated, assisting correct electrode placement. This new technique is much less uncomfortable and highly satisfactory EMG recordings are obtained.
Electromyography↗
Mu-, delta-, kappa-opioid receptors and their subtypes. A critical review with emphasis on radioligand binding experiments.
Since the early 1970's, when specific binding sites for opiates were first described, there has been a vast literature on opiate receptors, their subtypes, and even the multiplicity of these subtypes. In the present review, the signal transduction pathways, structure, and brain and spinal cord localization of the established subtypes (mu, delta, kappa) are reviewed. In addition, evidence suggesting heterogeneity of these subtypes, in particular from radioligand binding studies, is discussed critically.
Amino Acid Sequence↗
Characterization of [3H]CGS 19755 binding sites in the rat spinal cord.
[3H]Cis-4-phosphonomethyl-2-piperidine carboxylic acid ([3H]CGS 19755) was used to investigate the pharmacology and characteristics of the N-methyl-D-aspartate (NMDA) receptor recognition site from Triton X-100-treated membranes of rat spinal cord and cerebral cortex. The association of [3H]CGS 19755 was biphasic in both spinal cord and cerebral cortical membranes reaching a maximum after 5 min of incubation then decreasing to a steady level after an additional 10 min, suggesting that a proportion of the binding is unstable. The dissociation of the stable binding component was biphasic with rate constants at 4 degrees C of 1.55 and 0.020 min-1 for the spinal cord and 1.48 and 0.051 min-1 for the cerebral cortex. These multiple sites could not be captured in the saturation studies which were best fitted to a one-site model using non-linear regression analysis. Depending on the time of incubation with [3H]CGS 19755, KD and Bmax values differed; 9.9-26.1 nM and 25-96 fmol/mg protein vs 14.0-26.5 nM and 449-900 fmol/mg protein for spinal cord and cerebral cortex, respectively. The rank order of potency of inhibiting [3H]CGS 19755 binding was similar in both tissues: L-glutamate > CGS 19755 = CPP > NMDA. The specific NMDA agonist cis-2,4-methanoglutamate potently inhibited [3H]CGS 19755 binding as did MDL 100,925, although the latter was one order of magnitude less potent in the spinal cord than in the brain. The Hill coefficients were significantly lower than unity. In both tissues, AMPA, kainate and glycine competed poorly with [3H]CGS 19755.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Characterization of [3H]inositol 1,4,5-trisphosphate binding sites in human temporal cortical and cerebellar membranes.
The characteristics of [3H]Ins(1,4,5)P3 binding to human temporal cortical and cerebellar membranes have been determined and compared with the binding to calf cerebellar membranes. Association and dissociation of ligand was very rapid, k1 and k-1 values of the order of 7 x 10(7) M-1 min-1 and 0.2 min-1, respectively. KD values were 2.7 and 3.5 nM for temporal cortex and cerebellum, respectively. The corresponding Bmax values were 165 and 482 fmol/mg protein. Binding was influenced in a biphasic manner by calcium. The temporal cortical binding was inhibited by Ins(1,4,5)P3 and analogues with the following IC50 values (nM): Ins(1,4,5)P3 9.5 and 6.2 (two different salts from different sources), Ins(2,4,5)P3 42, Ins(1,3,4,5)P4 670, Ins(1,2,5,6)P4 2620, Ins(3,4,5,6)P4 4300, Ins(1,3,4,5,6)P5 5490, InsP(6)5280, Ins(4,5)P2 2600, Ins(1)P 3300, with the IC50 values for Ins(1,5,6)P3, Ins(1,4)P2 and Ins(4)P being > 25 microM. The IC50 value for heparin was 2.1 micrograms/ml. A similar pattern was seen in the cerebellum. In both tissues, the Hill slopes were near unity for all compounds except Ins(3,4,5,6)P4, where the slope was 0.4. The calf cerebellum had a similar ligand specificity (although the potency was generally lower) when values were expressed relative to that of Ins(1,4,5)P3, with the possible exception of Ins(1,3,4,5)P4, which had a greater relative potency. These data would suggest that in the human temporal cortex and cerebellum, [3H]Ins(1,4,5)P3 binding sites are expressed in different densities, but have similar properties. There may, however, be species differences in the [3H]Ins(1,4,5)P3 recognition site.
Animals↗