Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

At least 19 recordsLinked to original sources

PubMed2003

Biochemical and ultrastructural analyses of IgLON cell adhesion molecules, Kilon and OBCAM in the rat brain.

Kilon (kindred of IgLON) and opioid-binding cell adhesion molecule belong to the IgLON subgroup of immunoglobulin superfamily together with the limbic system-associated membrane protein and neurotrimin. In the present study, we have analyzed biochemical and ultrastructural characterization of Kilon and opioid-binding cell adhesion molecule such as regional and developmental expression patterns, light and electron microscopic localization, and intermolecular interactions. Western blotting revealed a widespread distribution pattern of Kilon with high expression levels in the olfactory bulb, cerebral cortex, diencephalon, hippocampus, and cerebellum and low expression levels in the medulla oblongata and spinal cord. In contrast, opioid-binding cell adhesion molecule showed a regionally restricted expression pattern with high levels only in the cerebral cortex and hippocampus. Expression of Kilon and opioid-binding cell adhesion molecule was increased gradually during postnatal development and maintained until adulthood. Light microscopic immunohistochemistry demonstrated that the localization of opioid-binding cell adhesion molecule and Kilon coincided well with that of vesicle-associated membrane protein 2, a synaptic marker protein, in the cerebral cortex and hippocampus of adult brain. In the cerebellum, Kilon-immunoreactive puncta were observed to colocalize well with that of vesicle-associated membrane protein 2, while opioid-binding cell adhesion molecule immunoreactivity was observed only at part of synaptic glomeruli in the granular layer and rare in the molecular layer. Electron microscopic analysis revealed that Kilon and opioid-binding cell adhesion molecule immunoreactivity was observed mainly at postsynaptic sites of dendritic and somatic synapses in adult cerebral cortex and hippocampus. Only trace levels of Kilon and opioid-binding cell adhesion molecule were detected in the soluble fraction of a cortical homogenate, although a substantial amount of F3 was present in the soluble fraction. A binding analysis using a cross-linker and the immunoprecipitation technique demonstrated that Kilon and opioid-binding cell adhesion molecule interacted heterophilically and homophilically. These findings show that Kilon and opioid-binding cell adhesion molecule are clearly distinguishable from each other in regional expression and localization, and binding patterns. These differences possibly represent diverse functions of each IgLON molecule.

Animals↗

PubMed2003

[Surgical treatment for pulmonary metastases from colorectal cancer].

Blalock first reported pulmonary resection for metastatic colorectal cancer in 1944. Since then, surgical resection of pulmonary metastases has been generally accepted as a standard therapeutic procedure in properly selected cases. Recently, the criteria of eligibility have been progressively expanded according to the development of radiological diagnosis using helical computed tomography (CT), widespread of minimum invasive video-assisted thoracic surgery. In this review summarized the surgical treatment of pulmonary metastases from colorectal cancer based on the recent literatures. Major areas of controversy remain with respect to the following aspects: prognostic factors (i.e., number of metastases, size of tumor, disease free interval, preoperative serum carcinoembryonic antigen level), procedure of operation (i.e., role of video-assisted thoracic surgery, lymphonode dissection), indication of surgical treatment on metastases both lung and liver, role of repeat thoracotomy for recurrence. For all above-mentioned points it appeared reasonable to try to the cooperative multicentric clinical prospective study.

Colorectal Neoplasms↗

PubMed2002

Toxicity assessment of 255 chemicals to pure cultured nitrifying bacteria using biosensor.

The bioassay has been attracting attention as a method of toxicity assessments of micropollutants in the environment. In this study, we report the characteristics (selectivity and sensitivity) of the nitrifying bacteria biosensor for 255 kinds of chemicals as a model of chemical contaminant in the environment and the results of evaluation of mixed samples of several substances. In the nitrifying bacteria respiration inhibition test using the biosensor, 56 chemicals were detected. It was found that this biosensor is especially sensitive to seven chemicals that have a thiocarbonyl functional group (>C=S), such as a thioamide group of thiocarbamate group. These chemicals are considered to specifically inhibit AMO by chelation of copper. The samples consisted of a mixture of seven types of anilines that inhibit respiration in the bacteria, a mixture of five types of chlorophenols, and a mixture of eight types of substances that contain thiocarbonyl groups were examined. All of the mixed samples inhibited the respiration of the nitrifying bacteria more than 10% by the inhibition rate, and observed a synergistic effects of the substances in the samples.

Aniline Compounds↗

PubMed2001

Disparate effects of interleukin 11 and thrombopoietin on megakaryocytopoiesis in vitro.

The effects of interleukin-11 (IL-11) and thrombopoietin (TPO) on murine megakaryocytopoiesis were studied using a serum-free culture system. Acting alone, both IL-11 and TPO increased the number of acetylcholinesterase (AchE)(+)cells (megakaryocytes), the latter being more potent than the former. TPO, but not IL-11, increased the mean AchE activity per megakaryocyte (AchE activity/megakaryocyte). TPO increased both the number of megakaryocytes with high ploidy, and of those with low ploidy. In contrast, IL-11 increased only the number of megakaryocytes with high ploidy. The effect of TPO on megakaryocyte ploidy was stronger than that of IL-11. Both IL-11 and TPO increased the proportion of large megakaryocytes, but the latter was more potent than the former. While the stimulatory effects of IL-11 and TPO on the number of megakaryocytes were enhanced by IL-3 or stem cell factor (SCF), synergism of IL-11 or TPO with IL-3 or SCF in stimulating AchE activity/megakaryocyte was inconsistent. IL-11 and TPO stimulated the formation of colony-forming units of megakaryocyte in the presence of IL-3, but not alone, with similar maximum colony numbers for both cytokines. Our findings thus demonstrate that IL-11 principally stimulates megakaryocyte maturation rather than the proliferation of megakaryocytes, whereas TPO stimulates both.

Acetylcholinesterase↗

PubMed2001

Stereoselective effect of (R)- and (S)-1-methyl-1,2,3,4-tetrahydroisoquinolines on a mouse model of Parkinson's disease.

We carried out behavioral, pathological, and biochemical studies in order to determine whether the stereo-structure of 1-methyl-1,2,3,4-tetrahydroisoquinoline (1-MeTIQ) affects the onset of Parkinson's disease-like symptoms, which are induced by 1,2,3,4-tetrahydroisoquinoline (TIQ) in mice. Pretreatment with (R)-1-MeTIQ or its racemate (RS)-1-MeTIQ prevented the TIQ-induced bradykinesia. Pretreatment with a combination of L-DOPA and carbidopa significantly prevented subsequent TIQ-induced bradykinesia. Furthermore, the pathological study demonstrated that either (R)-1-MeTIQ or its racemate protected against TIQ-induced loss of tyrosine hydroxylase-positive cells of the substantia nigra pars compacta. (R)-1-MeTIQ and its racemate also prevented the TIQ-induced reduction in the levels of dopamine and its metabolites in the striatum. Serotonin and its metabolite were not affected by repeated administration of (RS)-1-MeTIQ or its derivatives. On the other hand, (S)-1-MeTIQ induced moderate but significant bradykinesia, whereas (R)-1-MeTIQ did not induce this behavioral abnormality at all. In addition, (S)-enantiomer prevented the onset of TIQ-induced bradykinesia, though to a lesser extent than did either (R)-enantiomer or its racemate. However, (S)-enantiomer did not prevent the loss of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta. We concluded that (R)-1-MeTIQ, and not (S)-enantiomer, plays a crucial role in protection against TIQ-induced parkinsonism, a fact which suggests that enantiomeric biochemical events such as 1-MeTIQ biosynthesis may participate in the pathogenesis of Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2001

Expression of a tumor-associated antigen RCAS1 in hepatocellular carcinoma.

RCAS1 has been reported as a tumor-associated antigen in uterine and ovarian carcinomas. In vitro studies on RCAS1 indicated that it might function as an apoptosis-inducing factor since binding between RCAS1 and its receptor induced apoptosis in receptor-expressing cells. In this study, 68 surgically resected samples of hepatocellular carcinoma (HCC) were prepared and RCAS1 expression was examined immunohistochemically, because RCAS1 was also positive in all HCC cell lines tested. Clinical and pathological parameters were then compared between RCAS1-positive and -negative HCC cases. As a result, RCAS1 is expressed in 26.5% of HCC cases and vascular invasion is observed at a much higher rate in the RCAS1-positive cases (72.2%) than in RCAS1-negative cases (24.0%). RCAS1 is not an antigen specific for gynecological cancers. In HCC cases, the RCAS1-positive percentage is not high, however, RCAS1-positive HCCs exhibited a trend towards invasive character.

Animals↗

PubMed2001

Biochemical and pathological study of endogenous 1-benzyl-1,2,3,4-tetrahydroisoquinoline-induced parkinsonism in the mouse.

We administered 1-benzyl-1,2,3,4-tetrahydroisoquinoline (1-BnTIQ; 80 mg/kg, i.p.), an endogenous neurotoxin known to cause bradykinesia, the Parkinson's disease-like symptom, in order to obtain biochemical and pathological evidence of behavioral abnormalities. Immunohistochemical analysis demonstrated that 1-BnTIQ did not decrease the number of tyrosine hydroxylase-positive cells in the substantia nigra. Biochemical analysis demonstrated significantly increased striatal dopamine (DA) content, while DA metabolites in the striatum remained at control levels. We concluded that the 1-BnTIQ-induced bradykinesia has a different mechanism of action than that underlying the MPTP-induced depletion of striatal DA neurons.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2001

beta-Phenylethylamine modulates acetylcholine release in the rat striatum: involvement of a dopamine D(2) receptor mechanism.

We examined the effects of beta-phenylethylamine on striatal acetylcholine release in freely moving rats using in vivo microdialysis. beta-Phenylethylamine at 12.5 mg/kg, i.p. did not affect acetylcholine release in the striatum, whereas 25 and 50 mg/kg, i.p. immediately induced an increase in acetylcholine release in the striatum at 15-45 min. This increase following intraperitoneal administration of beta-phenylethylamine (25 mg/kg) was not affected by locally applied SCH-23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine, 10 microM), a dopamine D(1) receptor antagonist, nor by raclopride (10 microM), a dopamine D(2) receptor antagonist. The increased release of acetylcholine induced by beta-phenylethylamine was suppressed by local infusion of tetrodotoxin (1 microM). In contrast, the extracellular acetylcholine level in the striatum was significantly decreased by local application of beta-phenylethylamine (10 and 100 microM) in the striatum via a microdialysis probe. The decrease was completely blocked by local co-application of raclopride (10 microM). The beta-phenylethylamine-induced decrease in striatal acetylcholine release was not affected by co-perfusion with SCH-23390 (10 microM). These results indicate that systemic administration of beta-phenylethylamine increases acetylcholine release, whereas locally applied beta-phenylethylamine decreases striatal acetylcholine release in freely moving rats. Furthermore, the dopaminergic system, through the dopamine D(2) receptor, is involved in the locally applied beta-phenylethylamine-induced decrease in acetylcholine in the striatum.

Acetylcholine↗

PubMed2001

Kinetic analysis of megakaryopoiesis induced by recombinant human interleukin 11 in myelosuppressed mice.

Recombinant human interleukin 11 (rhIL-11) has previously been shown to ameliorate thrombocytopenia in several animal models. To elucidate the mechanisms involved in rhIL-11-induced hematopoiesis, a kinetic analysis of megakaryopoiesis was performed in mitomycin C (MMC)-induced myelosuppressive mice. Mice intravenously injected with MMC (2 mg/kg) for two consecutive days from day -1 developed severe thrombocytopenia with a nadir of platelet counts at 24x10(4)/microl on day 12 and neutropenia. Treatment with rhIL-11 (500 microg/kg/day) from day 1 to 21 significantly ameliorated the degree and duration of thrombocytopenia and enhanced the platelet recovery, and also enhanced the recovery from neutropenia. In MMC-treated mice, the decreases in bone marrow megakaryocyte progenitors and megakaryocyte counts preceded the decrease in platelet counts by MMC treatment. RhIL-11 induced an increase in the number of megakaryocyte progenitors from day 4 to 14, followed by an increase in the megakaryocytes by day 20. There was a ploidy shift in megakaryocytes towards lower ploidy cells by day 9 in myelosuppressed mice. RhIL-11 caused a shift towards a higher ploidy with 32 and 64N on day 4, and 32N on day 14. These results suggest that rhIL-11 ameliorates the thrombocytopenia via the stimulation of both the maturation and commitment followed by the proliferation of megakaryocytic cells.

Alkylating Agents↗

PubMed2001

Immunohistochemical phenotypic alterations of rabbit autologous vein grafts implanted under arterial circulation with or without poor distal runoff-implications of vein graft remodeling.

Although intimal hyperplasia is a major cause limiting the long-term patency of the vein grafts, its precise mechanisms, including the effect of poor runoff, has not yet been well characterized. We thus designed the present study to try to determine the effect of poor runoff arterial flow to the phenotypic alterations of the graft wall by immnohistochemistry using anti-intermediate filaments (alpha-SM actin, desmin, and vimentin) and anti-myosin heavy chain (SM1, SM2, and SMemb) specific antibodies. Vein grafts implanted under the poor runoff hind limb of rabbits showed enhanced intimal hyperplasia, however, no apparent difference in the cytoskeleton expression, including intermediate filaments and MHC, between two groups until 4 weeks. Interestingly, six of eight vein grafts at 2 weeks after implantation in both groups showed the accumulations of perivascular fibroblast-like phenotype (negative for SM1, alpha-SM actin, and desmin) in some parts of the outer neointima, whereas the inner neointima at 2 weeks and the whole neointima at 4 weeks were mainly occupied by a smooth muscle phenotype (positive for these three). Although the cellular origin of these cells is still unknown, these results suggest that the migration of non-muscle mesenchymal cells is involved in the neointima and thus may provide a clue for better understanding vein graft remodeling.

Anastomosis, Surgical↗

PubMed2001

Hepatic nodular hyperplasia in a boy with Alagille syndrome: CT and MR appearances.

A boy with Alagille syndrome complicated by hepatic nodular hyperplasia (HNH) is reported. During pre-transplantation evaluation, CT and MRI revealed a large hepatic lesion with multiple small nodular lesions. Angiography demonstrated a large hypervascular lesion and CT arterial portography (CTAP) showed a portal perfusion defect corresponding to the lesion. CTAP also revealed large portal vein branches running through the lesion. Although hepatocellular carcinoma is known to accompany Alagille syndrome, HNH should also be considered when large vessels running through the lesion are demonstrated.

Alagille Syndrome↗

PubMed2001

Characteristics of multicentric hepatocellular carcinomas: comparison with intrahepatic metastasis.

Characteristics of multicentric hepatocellular carcinomas (HCCs) remain obscure. We therefore aimed to clarify them and compare them with HCC with intrahepatic metastases. A series of 118 patients who had definite hepatitis C viral status and multinodular HCC were divided into two groups: a multicentric occurrence (MO) group (n = 38), with multicentric HCCs; and an intrahepatic metastasis (IM) group (n = 80), with HCC having intrahepatic metastases. Clinicopathologic variables, including the patient's survival and disease-free survival rates, were compared between the MO and IM groups. Univariate analysis revealed the presence of esophageal varices, the presence of hepatitis C virus infection, a platelet count of less than 10 x 10(4)/microliter, hepaplastin test, gamma-globulin, the histologically active hepatitis, tumor size, des-gamma-carboxy prothrombin > 0.1 AU/ml, positive portal vein invasion, and histologic grade as discriminating factors. The MO score to differentiate multicentric HCCs from intrahepatic metastatic HCCs was determined using the following four independent factors selected by a stepwise regression analysis: the presence of hepatitis C virus infection, a platelet count of less than 10 x 10(4)/microliter, tumor size, and histologic grade. The sensitivity and specificity of the MO scores using those factors were 84% and 70%, respectively, when the cutoff value was 0.4. The disease-free survival rate in the MO group was similar to that in the IM group, whereas the survival rate in the MO group was significantly better than that in the IM group. The multivariate analysis revealed the multicentric occurrence of HCC as one of the independent prognostic factors. Clinicopathologic factors differentiating multicentric HCCs from intrahepatic metastatic HCCs were the presence of hepatitis C virus infection, a platelet count of less than 10 x 10(4)/microliter, small tumor size, and low histologic grade.

Carcinoma, Hepatocellular↗

PubMed2001

Effects of single and repeated administration of 1,2,3,4-tetrahydroisoquinoline analogs on the binding of [11C]raclopride to dopamine D2 receptors in the mouse brain.

We investigated the effects of intraperitoneal injection of 1,2,3,4-tetrahydroisoquinoline (TIQ) analogs and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the binding of [11C]raclopride to striatal dopamine D2 receptors in mice. The binding of [11C]raclopride, but not of [11C]N-methylspiperone or [11C]nemonapride with higher affinity, to the receptors was significantly decreased immediately after TIQ injection. Neither a dopamine transporter blocker induced such effect nor TIQ affected the dopamine transporter-radioligand binding. Among the compounds investigated, including parkinsonism-inducing TIQ and (R/S)-1-benzyl-TIQ, parkinsonism-preventing (R)- and (S)-1-methyl-TIQ, and probable N-methylated metabolites of TIQ and 1-methyl-TIQ, TIQ and (S)-1-methyl-TIQ had the strongest effect on the binding of [11C]raclopride, and N-methylated derivatives showed less of an effect than the respective parent compounds. The decrease in the binding of [11C]raclopride continued for 7 hours and was followed by an increase until 10 days after the single and subchronic administration of TIQ. These findings suggest that TIQ analogs profoundly stimulated dopamine release which resulted in the competitive inhibition of the binding of [11C]raclopride to dopamine D2 receptors, but did not induce degeneration of the receptors.

Animals↗

PubMed2001

The role of macroscopic classification in nodular-type hepatocellular carcinoma.

BACKGROUND: Little has been reported on the role of macroscopic classification of hepatocellular carcinoma (HCC). We hypothesized that macroscopic classification of HCC might have a strong correlation with long-term prognosis after hepatectomy. METHODS: Four hundred and four patients with a macroscopically nodular type of HCC who underwent a hepatectomy were studied. The patients were divided into three groups: single nodular (SN) group (n = 312); single nodular with extranodular growth (SNEG) group (n = 52); and confluent multinodular (CMN) group (n = 40). Clinicopathological variables were compared among the three groups. The patient survival rate was also compared among the three groups. Finally, a multivariate analysis was performed to clarify the independent significant variables of the long-term prognosis. To confirm the consistency of the results in small-size HCC, the same analyses were made using patients whose tumor size was equal to or less than 3 cm in diameter. RESULTS: The alpha-fetoprotein value, tumor size, and rate of absolute noncurative operation in the SNEG group were higher than in other groups. The positive rate of both portal vein invasion of cancer cells and intrahepatic metastasis in the SN group was lower than those in other groups. The rate of poorly differentiated histology in the SN group was lower than in the other groups. Patient survival in the SNEG group was worst among the three groups. However, patient survival showed no significant difference between the SN and CMN groups. The multivariate analysis showed that the presence of intrahepatic metastasis, the macroscopic classification of SNEG type, and absolute noncurative operation were independent poor prognostic indicators. The results for patients with small HCCs measuring equal to or less than 3 cm in diameter were quite similar to the results for the other patients. CONCLUSIONS: Among the three subtypes of macroscopically nodular type of HCCs, the SNEG type showed higher rates of portal vein invasion of cancer cells, intrahepatic metastasis, and poorly differentiated histology. The patient survival rate in the SNEG type was worst, and the SNEG type was an independent poor prognostic indicator. The macroscopic classification of HCC, especially the SNEG type, helps predict the long-term outcome after hepatectomy.

Carcinoma, Hepatocellular↗

PubMed2001

The role of overexpression and gene amplification of cyclin D1 in intrahepatic cholangiocarcinoma.

BACKGROUND/AIMS: Intrahepatic cholangiocarcinoma (ICC) is a primary liver malignant tumor with an extremely poor prognosis, but less attention has been directed to factors related to molecular carcinogenesis, including cell cycle proteins. We examined the expression and gene amplification of cyclin D1, the cell cycle regulating protein. Our objective was to evaluate correlations with clinicopathological factors in ICC. METHODS: Cyclin D1 overexpression and cellular proliferative activity (Ki-67 labeling index) were investigated immunohistochemically, and 20 cases were further investigated for cyclin D1 gene amplification, using differential PCR. We examined the correlation between the expression and gene amplification of cyclin D1 and clinicopathological factors, including overall survival in patients with ICC. RESULTS: Immunohistochemical analysis revealed an overexpression of cyclin D1 protein in 28 of 66 subjects with ICCs (42%). The cyclin D1 overexpression was associated with poor histological differentiation (P = 0.04), high cellular proliferative activity (P < 0.01), and a poor prognosis (P = 0.02) by univariate analysis, although it is not an independent prognostic factor by multivariate analysis. Cyclin D1 gene amplification was confirmed in five of the 20 patients. Of those five cases of ICC, all had poor histological differentiation, and four of the five ICCs (80%) showed evidence of cyclin D1 immunoreactivity. CONCLUSIONS: Overexpression and gene amplification of cyclin D1 are frequent and contribute to dedifferentiation and cellular proliferative activity of ICCs, and overexpression also indicates a poor prognosis for patients with ICC.

Adult↗

PubMed2001

Decreased expression of an ATP-binding cassette transporter, MRP2, in human livers with hepatitis C virus infection.

BACKGROUND/AIMS: To understand hepatic injury during the process of hepatitis viral infection, determination of liver-specific functions at molecular levels is critical. Because the transport of endogenous/exogenous toxic substances is an intrinsically important hepatic function, we examined whether expression of the ATP-binding cassette (ABC) transporter gene was affected in patients with hepatitis viral infection. METHODS: To determine which ABC transporter was expressed differently in patients with hepatic viral infection, we assayed the expression of MDR1, MDR3, MRP1, MRP2, and MRP3 in non-cancerous regions in the liver of 42 patients with hepatic tumors using both quantitative RT-PCR and immunological staining analysis, and compared the hepatic expression levels between patients with hepatitis viral infection and non-infected controls. RESULTS: Of the five ABC transporter genes studied, the mRNAs of MRP2 and MRP3 were highly expressed in the human liver. There was a significant reduction in MRP2 expression to 29% in the virus-infected liver. Treatment of hepatic cells with inflammatory cytokines resulted in decreased mRNA levels of MRP2 and decreased MRP2 promoter activity. CONCLUSIONS: The down-regulation of MRP2 might induce a failure in the transport of various genotoxic substances in the liver with hepatitis virus infection.

Adult↗

PubMed2001

Gait initiation in bilateral vestibular loss.

OBJECTIVE: Gait initiation is a transient procedure between orthostatic posture and steady-state locomotion and includes anticipatory anteroposterior (AP) and lateral movements. Commands for this task are located in some levels of brain stem, which modulates activity of central pattern generator in the spinal cord. The purpose of this work was to explore the role of the vestibular system in this voluntary stepping. METHODS: Six patients with chronic bilateral vestibular loss (BVL) were measured by means of a large force plate (70 cm x 120 cm ) and the displacement of the center of pressure (COP) during gait initiation was calculated. Measurement parameters comprised maximum distance (MD), velocity (MV) in the AP and lateral direction as well as for pre-, first- and second-step stages, and the angle of the COP trajectory. RESULTS: For all stages, BVL patients registered lower values for both MD and MV in the AP direction than did normal subjects. In the lateral direction, however, neither MD nor MV in BVL patients showed any difference from those of normals. The step angle of the COP trajectory was obviously reduced. CONCLUSION: These results suggest that in the AP direction, the vestibulospinal pathway can influence the locomotor related neural circuits, including the central pattern generator and supraspinal levels, by means of modifying the velocity and step length in order to stabilize the trunk. On the other hand, the control mechanism in the lateral direction may be different from that in the AP direction.

Adult↗

PubMed2001

Synthesis and evaluation of radiolabeled piperazine derivatives of vesamicol as SPECT agents for cholinergic neurons.

To diagnose and investigate neurodegenerative diseases affecting cholinergic neuron density, piperazine derivatives of vesamicol were synthesized and evaluated. Previously, we reported that trans-5-iodo-2-hydroxy-3-[4-phenylpiperazinyl] tetralin (DRC140, 1) possessed high selectivity for vesicular acetylcholine transporter (VAChT). In present study of the effect of alkyl substituents, we observed that the introduction of a methyl group into the ortho or meta positions of the phenyl group of 1 increased affinity for VAChT. trans-5-Iodo-2-hydroxy-3-[4-[2-methylphenyl] piperazinyl]tetralin (2) displayed high affinity and specificity for VAChT. The regional distributions of radioactivity in the rat brain correlated well with known patterns of central cholinergic innervation. [(123)I]2 is a potentially useful compound for SPECT imaging.

Animals↗