PubMed Health⌕ Search

Biomedical subjects

J Ge

Publications and source records attributed to J Ge.

At least 19 recordsLinked to original sources
PubMed1997

Coronary artery calcium in acute coronary syndromes: a comparative study of electron-beam computed tomography, coronary angiography, and intracoronary ultrasound in survivors of acute myocardial infarction and unstable angina.

BACKGROUND: Quantification of coronary artery calcified plaques by electron-beam CT (EBCT) may predict cardiovascular events. However, whereas advanced coronary atherosclerotic plaques can be identified, mildly stenotic lipid-rich (soft) plaques may be difficult to detect. The value of EBCT in a subgroup of patients has therefore been questioned. To investigate this, we evaluated patients with acute coronary syndromes by EBCT and compared the results with coronary angiography and, in patients with an indeterminate angiogram, intracoronary ultrasound (ICUS). METHODS AND RESULTS: EBCT was performed in 118 consecutive patients (57+/-11 years of age) with previous myocardial infarction (n=101) or unstable angina (n=17). A standard protocol requiring a CT density >130 Hounsfield units in an area > or =1.03 mm2 was used for the definition of coronary artery calcium. We found that 110 patients had moderate to severe coronary artery disease by coronary angiography, and 8 had either mildly stenotic plaques at a single site (4 patients, confirmed by ICUS) or nonatherosclerotic causes of the unstable coronary syndrome (4 patients). One hundred and five of the 110 patients (96%) with moderate to severe angiographic disease but only 1 of the 8 other patients (13%) had a positive EBCT. Patients with acute coronary syndromes and negative EBCTs were significantly younger than patients with positive EBCTs (46+/-12 versus 58+/-10 years, P<.001), and a higher percentage was actively smoking (100% of the smokers versus 46%, P<.05). CONCLUSIONS: The vast majority of patients with acute coronary syndromes and at least moderate angiographic disease have identifiable coronary calcium by EBCT. Those patients with negative EBCTs have minimal or no atherosclerotic plaque formation. They are younger and tend to be active cigarette smokers.

Acute Disease↗
PubMed1997

Distribution of S(-)-zacopride-insensitive [125I]R(+)-zacopride binding sites in the rat brain and peripheral tissues.

Increasing evidence indicates that the 5-HT3 receptor antagonist R(+)-zacopride labels an additional site in brain tissue that is not sensitive to 5-HT (non-5-HT R(+)-zacopride site, R(+)-site). Since the levels of R(+)-sites in the brain are relatively low, the present studies explored the use of [125I]R(+)-zacopride to label the R(+)-site; the incorporation of an [125I] atom considerably increasing the specific activity of the radioligand relative to [3H]R(+)-zacopride that has been utilised previously. Competition experiments with [125I]R(+)-zacopride (1.0 nM) binding to rat whole brain homogenates, in the presence of the 5-HT3 receptor antagonist granisetron (1.0 microM), identified that R(+)-zacopride and prazosin bound to two sites (pIC50: 7.59 and 5.28, respectively, for R(+)-zacopride; 6.75 and 4.42, respectively, for prazosin) whereas S(-)-zacopride and mianserin possessed relatively low affinity (pIC50: 4.37 and 3.80, respectively) while (-)sulpiride and 5-HT failed to compete for [125I]R(+)-zacopride binding at concentrations up to 10 microM. Autoradiographic radioligand binding studies using [125I]R(+)-zacopride (0.5 nM) identified a heterogeneous distribution of specific binding sites (defined by unlabelled R(+)-zacopride, 1.0 microM) throughout the rat brain. In the presence of a saturating concentration of granisetron (1.0 microM), highest levels of specific [125I]R(+)-zacopride, binding sites (defined by R(+)-zacopride, 1.0 microM; R(+)-site), were detected in the olfactory tubercle, thalamus, corpus callosum, colliculus, dorsal and median raphe nucleus, spinal cord and the pons (8.0-13.0 fmol/mg). Moderate densities of R(+)-sites were located in the striatum, nucleus accumbens, substantia nigra, ventral tegmental area, globus pallidus, septal nuclei, frontal cortex and cerebellum (2.0-7.9 fmol/mg). In the hippocampus, amygdala and cortical areas. R(+)-site levels were low but detectable (0.1-1.9 fmol/mg). [125I]R(+)-zacopride labelled R(+)-sites were also detected in some rat peripheral tissues, for instance kidney cortex, adrenal gland and liver (2.4-6.8 fmol/mg). The present results indicate that specific non-5-HT [125I]R(+)-zacopride sites are heterogeneously distributed throughout the rat brain and are expressed in various peripheral tissues.

Animals↗
PubMed1997

High-volume nonionic dimeric contrast medium: first experiences during complex coronary interventions.

Interventional cardiology is a rapidly developing field of medicine with annually increasing numbers of coronary interventions. Especially through the development of alternative techniques for coronary angioplasty, new indications have been found and more difficult lesions are tackled. Inevitably, such complex interventions are time-consuming and require high amounts of contrast medium. Newer, mostly nonionic agents have been developed with improved tolerability as well as fewer cardiac and renal side effects due to their nonionic, hydrophilic structure, and their osmolality isotonic to plasma. This study sought to investigate the effects of high-volume nonionic, dimeric contrast medium during coronary interventions with special emphasis on renal and hemodynamic side effects during routine hospital stays. Retrospectively, 25 consecutive patients (age 56 +/- 10 yr) with normal renal and cardiac function receiving > 500 ml of the nonionic dimeric contrast medium iodixanol during complex coronary interventions were analyzed. The analysis was based on serum creatinine levels 1 day before and 2 days after contrast medium administration for the monitoring of renal function. Additionally, heart rate and left ventricular pressures were evaluated before and after left ventricular angiography. Mean serum creatinine rose from 0.9 +/- 0.2 mg/dl to 1.1 +/- 0.2 mg/dl (P < 0.05) after 2 days of coronary intervention. Heart rate, left ventricular systolic pressure, and left ventricular end-diastolic pressure did not change significantly. No major side effects were encountered in the short follow-up period of 2 days. Based on this retrospective analysis, high-volume nonionic, dimeric contrast medium administration in patients without preexisting renal insufficiency is associated with little impairment of renal function, and has only minor hemodynamic and general side effects. Iodixanol 320 mg I/ml is well-tolerated and effective for the use of cardioangiography. Given the limitations of this retrospective analysis, future prospective studies should systematically address the effects of high-volume contrast medium administration in otherwise healthy patients as well as in high-risk patients undergoing coronary interventions.

Aged↗
PubMed1997

[Laser angioplasty and recanalization].

Percutaneous transluminal coronary balloon angioplasty (PTCA) still is the most frequently applied interventional technique for treatment of coronary artery disease. Plastic deformation of the obstructive plaque with creation of splits, intimal tears and dissections is the main mechanism of PTCA for lumen widening. As a result, acute complications due to flow limiting dissections and acute vessel closure can unpredictably occur resulting in myocardial infarction, urgent bypass surgery and death. Furthermore, long-term success of PTCA is limited by restenosis. In order to overcome these limitations of PTCA, alternative interventional techniques were developed, which instead of deforming the obstructive plaque ablate this tissue. These techniques include high and low speed rotational angioplasty, directional atherectomy, the transluminal extraction catheter, ultrasound angioplasty and laser (Light Amplification by Stimulated Emission of Radiation) angioplasty. 308 nm XeCl excimer laser angioplasty today is the laser technique of choice for clinical application. This pulsed laser requires direct contact to the obstructive plaque. It creates fast (< 200 microseconds) expanding gas bubbles which induce plaque ablation. Main indications for 308 nm XeCl excimer laser angioplasty are diffuse and long coronary lesions and total coronary occlusions. Despite promising initial results this technique showed no better acute and long-term results in comparison to PTCA for the treatment of these types of lesions ("Amsterdam-Rotterdam" Study, "Excimer Rotational Balloon Angioplasty Comparison" Study). As a result, this interventional technique was rarely applied for patient treatment. More recently, the concept of plaque ablation by 308 nm XeCl excimer laser angioplasty was renewed for the treatment of in-stent restenosis. This indication is being investigated in the "Laser Angioplasty of Restenosed Stents" trial. First results document the practicability and safety of this approach. Long-term results are awaited. With ongoing miniaturization, laser guidewires were developed for the recanalization of chronic total occlusions. The randomized multicenter "Total Occlusion Trial with Angioplasty assisted by Laser guidewire "Study documented a success rate of laser wire recanalization in up to 66% in contrast to 47.5% for mechanical wires only. Long-term results are still awaited. Technical and procedural progress including saline flush during laser application, homogeneous light distribution and the concept of smooth laser ablation is pushed foreward to make excimer laser angioplasty safer, more predictable and more effective.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Emergency stent implantation in the area of extensive muscle bridging of the anterior interventricular ramus after post-interventional dissection].

In a 64-year-old male patient with severe angina pectoris (CCS III) a systolic compression caused by a coronary muscle bridging in the left anterior descending artery could be detected by coronary angiography. Intravascular ultrasound (IVUS) as well as intracoronary Doppler examination showed a significant systolic reduction of the cross-sectional luminal area of 35.9% and a reduced coronary flow velocity ratio (CFVR) of 2.6. Two highly significant stenosis were detected proximal and distal of the muscle bridge. Percutaneous transluminal coronary angioplasty was performed at the distal lesion, resulting in a flow reducing dissection, and therefore subsequently a stent implantation was performed. Since the transition between the stent and the muscle bridge showed a severe flexion with continued systolic compression of the vessel, two further stents were employed to reinforce the entire area of the muscle bridging. A fourth stent was implanted in the proximal lesion. In the following angiographic and IVUS examinations a systolic compression was not detectable and the CFVR increased to 3.3. In the 6 months follow-up coronary angiography a restenosis in the stented area by intimal hyperplasia could be observed. However, IVUS showed all stents to be circular and fully expanded without signs of compression by the muscle bridge.

Aortic Dissection↗
PubMed1997

Effect of aversive stimulation on 5-hydroxytryptamine and dopamine metabolism in the rat brain.

The neurochemical consequences of aversive behavior based on novelty, rat social interaction, have been assessed in various rat brain regions utilizing high-performance liquid chromatography coupled with an electrochemical detector (HPLC-ECD) technique. The present studies indicated that compared to animals from the home cage, those exposed to the high-light aversive unfamiliar test condition, had significantly increased levels of 5-hydroxyindoleacetic acid (5-HIAA), the metabolite of 5-hydroxytryptamine (5-HT), in the tested brain regions including amygdala, entorhinal cortex, frontal cortex, temporal cortex, tuberculum olfactorium, hippocampus, nucleus accumbens, and striatum. The levels of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the metabolites of dopamine (DA), were increased in tuberculum olfactorium, nucleus accumbens, and striatum. When compared to the low-light familiar test condition (LF), the levels, following exposure to the highlight unfamiliar situation, of 5-HIAA were significantly increased in the amygdala, entorhinal cortex, tuberculum olfactorium, hippocampus, and nucleus accumbens, while the 5-HIAA levels remained unchanged in the frontal cortex, temporal cortex, and striatum. The DOPAC and HVA levels were also increased by the HU situation in the amygdala, tuberculum olfactorium, and nucleus accumbens. An increase was also found for the levels of DA in the amygdala. Such effects were prevented by diazepam or the 5-HT3 receptor antagonist ondansetron. It is concluded that the aversive test condition of the social interaction test (HU) increases 5-HT and DA turnover throughout the rat brain. Such effects might be related to the sensitivity to novel anxiolytic drug of the social interaction test.

Animals↗
PubMed1997

Autoradiographic mapping of brain 5-HT2A binding sites in P and in AA alcohol-preferring rats.

There is considerable evidence for an involvement of serotonergic mechanisms in the control of alcohol consumption. In the present study, an extensive 5-HT2A receptor autoradiographic investigation was carried out in two genetically selected rat strains, P and AA alcohol-preferring rats, respectively, as well as in the corresponding NP and ANA alcohol-nonpreferring rats. The aim was to determine if there is any common pattern in 5-HT2A binding site densities that may illuminate mechanisms of alcohol preference in these animals. For quantitating 5-HT2A binding sites, [3H]ketanserin (2 nM) was used. Nonspecific binding was measured in the presence of methysergide 10(-6) M. Results demonstrated a lower level (from 50 to 70%) of 5-HT2A binding sites in the layer IV of prefrontal cortex, frontal cortex, parietal cortex of P rats compared to NP controls. Similarly, in the claustrum, 5-HT2A binding density of P rats was 50% lower than that of NP rats, although this failed to achieve statistical significance. No difference was detected in the other areas investigated, including the olfactory tubercles, nucleus accumbens, caudate putamen, pyriform cortex, ventral tegmental area, temporal cortex, and entorhinal cortex. In AA rats, [3H]ketanserin binding density measured in these brain areas was very similar to that observed in ANA nonpreferring controls, and statistical analysis did not reveal any significant difference between the two rat lines. The present study confirms previous reports demonstrating lower densities of 5-HT2A binding sites in the P rats and provides the first autoradiographic evidence showing that such an alteration does not occur in AA rats. These findings suggest that the expression of high alcohol preference in genetically selected P and AA rats is not associated with a shared neurochemical alteration of the 5-HT2A receptor system.

Alcoholism↗
PubMed1997

Comparison of electron beam computed tomography with intracoronary ultrasound and coronary angiography for detection of coronary atherosclerosis.

OBJECTIVES: This analysis compared the results of electron beam computed tomography (EBCT) with those of coronary angiography and intracoronary ultrasound (ICUS) for the in vivo detection of coronary atherosclerotic plaques. BACKGROUND: EBCT is a new imaging modality for identification of coronary calcifications. Coronary angiography depicts advanced changes in coronary morphology, whereas ICUS is an established diagnostic tool that detects the early stages of coronary artery disease. METHODS: In 57 patients (54 +/- 9 years old), 267 coronary segments were analyzed with EBCT (3-mm slices, acquisition time 100 ms, threshold definition of coronary calcification at 130 Hounsfield units in an area > or = 1 mm2, Agatston calcium score), coronary angiography and ICUS. The analysis was based on the number and extent of coronary calcifications on EBCT, coronary lumen reduction on coronary angiography and plaque formation with and without ultrasound signs of calcifications on ICUS. RESULTS: Compared with coronary angiography, EBCT yielded a sensitivity of 66%, a specificity of 78%, a positive predictive value of 39% and a negative predictive value of 91%. Compared with ICUS, EBCT yielded an overall sensitivity of 66%, a specificity of 88% and an overall accuracy of 81%. For plaques with and without ultrasound signs of calcifications, the sensitivity of EBCT was 97% and 47%, specificity 80% and 75% and overall accuracy 82% and 69%, respectively. CONCLUSIONS: This in vivo correlation between ICUS and EBCT demonstrates that EBCT is a noninvasive method that helps to visualize the atherosclerotic process by localization and quantification of coronary artery calcifications. EBCT detects calcified plaques with high accuracy. Plaques without ultrasound signs of calcifications can be detected by EBCT but with lower sensitivity but equivalent specificity.

Adult↗
PubMed1997

Non-invasive assessment of cardiac physiology by tissue Doppler echocardiography. A comparison with invasive haemodynamics.

BACKGROUND: Tissue Doppler echocardiography reveals characteristic patterns of myocardial velocities within systole and diastole which are not well understood. AIM: The purpose of this study was to determine the relationship of myocardial velocity patterns, as assessed by tissue Doppler echocardiography, to the contraction and relaxation phases of the cardiac cycle, as determined during cardiac catheterization. METHODS: Recordings of left ventricular/aortic and left ventricular/pulmonary wedge pressures were obtained simultaneously with apical tissue Doppler echocardiographic images of the left ventricle. A total of 210 cardiac cycles from 22 patients (mean age 58 years, 18 male) undergoing cardiac catheterization were analysed. The time intervals of the different phases of the cardiac cycle were measured from the pressure tracings. These time intervals were correlated to the interfaces of colour myocardial velocity patterns obtained by M-mode tissue Doppler echocardiography. RESULTS: There was a good correlation between the time intervals assessed haemodynamically and those based on the different velocity interfaces obtained with M-mode tissue Doppler echocardiography. Comparable time intervals (from the R wave) obtained by pressure recordings and tissue Doppler echocardiography were, respectively: isovolumic contraction (70 +/- 14 vs 67 +/- 9 ms, r = 0.79); rapid ejection (206 +/- 54 vs 202 +/- 49 ms; r = 0.95); late ejection (357 +/- 36 vs 346 +/- 42 ms. r = 0.93); isovolumic relaxation (405 +/- 43 vs 409 +/- 56 ms; r = 0.95); rapid filling (514 +/- 67 vs 523 +/- 64 ms, r = 0.91); diastasis (697 +/- 153 vs 709 +/- 146 ms, r = 0.98); atrial contraction (890 +/- 128 vs 899 +/- 132 ms, r = 0.96). CONCLUSION: Tissue Doppler echocardiography has the potential to accurately measure the different phases of the cardiac cycle which until now could only be determined invasively. It may provide a sensitive method for the assessment of changes in both cardiac contraction and relaxation in different clinical settings.

Atrial Fibrillation↗
PubMed1997

Intravascular ultrasound in patients with acute pulmonary embolism after treatment with intravenous urokinase and high-dose heparin.

OBJECTIVE: To compare the diagnostic value of intravascular ultrasound (IVUS) with angiography in patients with pulmonary embolism. DESIGN: Open, prospective clinical study. SETTING: Two university hospitals. PATIENTS: Angiography and IVUS were used in 11 patients (5 men) (mean (SD) age 50 (18) years) with acute pulmonary embolism. INTERVENTIONS: At a mean (SD) of 6 (4) hours after thrombolytic therapy with urokinase and full-dose heparin, all patients underwent pulmonary artery angiography. Then 3.5 F mechanical, 20 or 30 MHz IVUS catheters were advanced into the pulmonary circulation. MAIN OUTCOME MEASURES: The pulmonary circulation was studied by both methods to detect the presence of thrombus, and a modified Miller score (assessing perfusion defects only and not velocity of flow) was used to quantify the angiographic images. RESULTS: The modified Miller score was mean (SD) 7.4 (2.3) points. 168 pulmonary artery segments (diameter range 2-14 mm) were studied by angiography and IVUS. On angiography, seven segments showed complete obstruction and 49 partial obstruction; 112 were normal. Two distinct types of thrombus formation were found by IVUS. Type A thrombus only partly adhered to the wall but otherwise was mobile and type B predominantly adhered to the wall. IVUS confirmed all seven angiographically complete obstructions but missed three (6%) of the 49 partial occlusions. Forty (87%) of the remaining 46 segments had type A thrombus and six (13%) type B. IVUS indicated a thrombus in 38 (34%) of the 112 angiographically normal segments; 20 (53%) showed a type A pattern and 18 (47%) a type B pattern (P < 0.001). CONCLUSION: IVUS was more sensitive than angiography in detecting thrombus but the clinical impact of this finding is not clear as yet.

Acute Disease↗
PubMed1996

Assessment of chromatographic peak purity by means of artificial neural networks.

An improved chemometric approach is proposed for assessing chromatographic peak purity by means of artificial neural networks. A non-linear transformation function with a back-propagation algorithm was used to describe and predict the chromatographic data. The Mann-Whitney U-test was used for the concluding the purity of the chromatographic peak. Simulation data and practical analytical data for both pure and mixture samples were analysed with satisfactory results. A prior knowledge of the impurity and the related compound is unnecessary when a slight difference between their chromatogram and spectrum exists. The performance on simulated data sets by this approach was compared with the results from principal component analysis.

Algorithms↗
PubMed1996

[125I]S(-)-zacopride labels a novel 5-hydroxytryptamine sensitive recognition site in rat duodenum and ileum.

Autoradiographic binding studies using [125I]S(-)-zacopride (0.1 nM) identified non-5-HT3 specific binding sites (defined by 5-hydroxytryptamine (5-HT), 1.0 microM) in the rat duodenum and ileum and some other peripheral tissues (adrenal gland, liver, stomach, kidney and spleen). In the rat duodenum and ileum, saturation studies with [125I]S(-)-zacopride indicated that the specific binding was saturable and of high affinity to an apparently homogenous population of binding sites (duodenum Bmax = 1.88 fmol/mg, Kd = 0.078 nM; ileum Bmax = 1.60 fmol/mg, Kd = 0.071 nM). Competition studies with slices of either duodenum or ileum indicated that the pharmacology of the [125I]S(-)-zacopride recognition site in both tissues was comparable but differed from all 5-HT receptors and uptake sites reported to date. However, the [125I]S(-)-zacopride recognition site displayed some pharmacological and regional similarity to the 5-HT1P recognition site: The sensitivity of the [125I]S(-)-zacopride binding in the duodenum and ileum to GTP indicates that the radiolabelled recognition site may represent a functional G-protein coupled receptor.

Animals↗
PubMed1996

Alterations in angiotensin AT1 and AT2 receptor subtype levels in brain regions from patients with neurodegenerative disorders.

The present studies assessed the levels of [125I][Sar1,ILE8]angiotensin II-labelled angiotensin AT1 and AT2 receptor recognition sites in homogenates of various brain areas (including caudate nucleus, putamen, substantia nigra, hippocampus, frontal cortex, temporal cortex and cerebellum) from patients with clinically diagnosed Parkinson's disease, Huntington's disease and Alzheimer's disease and those from age-, sex- and post-mortem delay-matched neurologically and psychiatrically normal patients. Radiolabelled angiotensin AT1 receptor recognition site levels were significantly decreased by approximately 70%, 70% and 90% in the caudate nucleus, putamen and substantia nigra, respectively, from patients with Parkinson's disease relative to matched controls. Furthermore, radiolabelled angiotensin AT2 receptor levels were decreased by some 60% in the caudate nucleus of patients with Parkinson's disease relative to control patients. In brain tissue homogenates from patients with Huntington's disease, the angiotensin AT1 receptor recognition site levels were decreased by approximately 30% in putamen relative to the control patients whilst angiotensin AT2 receptor levels were increased by some 90% in the caudate nucleus relative to the control patients. In brain tissue homogenates from patients with Alzheimer disease, the angiotensin AT2 receptor recognition site levels were significantly increased by approximately 200% in the temporal cortex relative to the control patients. The present results indicate that the reduction of angiotensin AT1 and/or AT2 receptor recognition site levels in the caudate nucleus, putamen and substantia nigra correlates with the principal neuropathology associated with Parkinson's disease and as such indicates that at least a significant population of angiotensin AT1 and AT2 receptors are located on the human dopaminergic nigrostriatal pathway. In addition, the marked increase in the levels of angiotensin AT2 receptor recognition sites in temporal cortex from patients with Alzheimer's disease correlates with some other markers associated with the renin-angiotensin system previously investigated in tissue from patients with this neurological disease.

Aged↗
PubMed1996

Equipment configuration and procedures: preferences for interventional microtherapy.

Magnetic resonance imaging (MRI), computed tomography, and electron beam tomography scanners are built for radiologic diagnosis. With increasing frequency they are being used in the field of interventional Microtherapy to permit transparent visualization of the therapeutic field. Each of these scanners can be combined with endoscopy, fluoroscopy/digital subtraction angiography, and ultrasound units for hybrid imaging techniques as well as with therapeutic systems like lasers or radiofrequency. MRI affords 3D localization without x-ray exposure. Open access and keyhole imaging allow nearly real time guidance of instruments. Minimally invasive techniques using endoscopes and hybrid tomographic guidance result in improved tip tracking of microinstruments and reduced complications. This safer access into the body will lead to interdisciplinary cooperation with the potential for large cost reductions. This report summarizes our experience regarding which of the hybrid imaging suites is best suited for procedures including among others drug instillations, prosthesis (stent) implantation, or microoperations (endoscopic diskectomy/sequestrectomy), and physiological measurements simultaneously.

Diagnostic Imaging↗
PubMed1996

Autoradiographic distribution of [3H]-(S)-zacopride-labelled 5-HT3 receptors in human brain.

Autoradiographic binding studies using the 5-HT3 (5-hydroxytryptamine3) receptor radioligand, [3H]-(S)-zacopride (0.5 nM), identified a heterogeneous distribution of specific binding sites (defined by granisetron, 1 microM) throughout the human brain. Highest radiolabelled 5-HT3 receptor densities were detected in discrete nuclei within the brainstem (nucleus tractus solitarius, area postrema, spinal trigeminal nerve nucleus; 50-200 fmol/mg tissue equivalent) with more modest levels of expression in the forebrain (e.g. hippocampus, nucleus accumbens, putamen, caudate; 4-17 fmol/mg tissue equivalent). Within the hippocampal formation, radiolabelled 5-HT3 receptors were differentially distributed with highest levels in the granule cell layer of the dentate gyrus. Saturation studies with [3H]-(S)-zacopride (0.05-16 nM; non-specific binding defined by granisetron, 10 microM) binding to homogenates of human putamen indicated that [3H]-(S)-zacopride (0.05-16 nM; non-specific binding defined by granisetron, 10 microM) binding to homogenates of human putamen indicated that [3H]-(S)-zacopride labelled an apparently homogenous population of binding sites (Bmax = 72 + 7 fmol mg-1 protein, pKd = 8.69 +/- 0.09, Hill coefficient = 0.99 +/- 0.06, mean +/- SEM, n = 4). The pharmacological profile of [3H]-(S)-zacopride binding to homogenates of putamen indicated the selective labelling of the human variant of the 5-HT3 receptor. The marked differences, however, in the pharmacology (e.g. low affinity for D-tubocurarine) and relative distribution (e.g. presence of 5-HT3 receptors in the human extrapyramidal system) of 5-HT3 receptors in the human forebrain when compared with other species further necessitates caution in predicting clinical responses based on data generated in animal models of disease.

Adult↗