Uptake Sites (uptake + site)

Distribution by Scientific Domains


Selected Abstracts


Norepinephrine Uptake Sites in the Locus Coeruleus of Rat Lines Selectively Bred for High and Low Alcohol Preference: A Quantitative Autoradiographic Binding Study Using [3H]-Tomoxetine

ALCOHOLISM, Issue 5 2000
Bang H. Hwang
Background: The locus coeruleus (LC) is the largest norepinephrinergic cell group in the central nervous system and contains a high density of norepinephrine (NE) uptake sites. Alcohol-preferring (AP) rats and high,alcohol-drinking (HAD) rats are selectively bred for high alcohol preference, whereas alcohol-nonpreferring (NP) rats and low,alcohol-drinking (LAD) rats are bred for low alcohol preference. However, it is unknown whether NE uptake sites in the LC are associated with alcohol preference in AP and HAD rats when compared with their respective control rats, NP and LAD rats. This study was designed to examine this question. Methods: Animals were decapitated and brains were removed, frozen with dry ice powder, and stored in a deep freezer. The LC tissue blocks were cut into 14 , cryostat sections, collected on glass slides, and incubated with 0.6 nM [3H]-tomoxetine in 50 mM Tris-HCl buffer system. For nonspecific binding, 1 ,M desipramine was added to the radioactive ligand. Sections were rinsed, quickly dried, and processed for quantitative autoradiography. In addition, galanin content in the LC was also studied. Results: The LC possessed a high density of [3H]-tomoxetine binding sites. There were fewer tomoxetine binding sites (fmol/mg protein) in the AP rats (433.0 ± 8.1) than in the NP rats (495.6 ± 3.7). HAD rats (386.5 ± 13.2) also possessed fewer tomoxetine binding sites than LAD rats (458.7 ± 10.1). Galanin content in the LC was similar between AP and NP rats and between HAD and LAD rats. Conclusions: Because both AP rats and HAD rats were selectively bred for alcohol preference, the finding of consistently low levels of [3H]-tomoxetine binding in the LC of these two lines of rats with high alcohol preference suggests that down-regulation of NE transporters in the LC of AP and HAD rats may be associated with alcohol-seeking behavior. A possible involvement of the coerulear NE uptake sites in depression is also discussed. Galanin in the LC may not relate to alcohol preference. [source]


Hypericum caprifoliatum (Guttiferae) Cham.

FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 6 2006
& Schltdl.: a species native to South Brazil with antidepressant-like activity
Abstract In this work, previously published and unpublished results on biological activity of Hypericum caprifoliatum, a native specie to South Brazil, are presented. Lipophilic extracts obtained from this species showed an antidepressant-like activity in mice and rat forced swimming test. Results from in vivo experiments suggest an effect on the dopaminergic transmission. Besides that, in vitro experiments demonstrated that the extract and its main component (a phloroglucinol derivative) inhibit monoamine uptake in a concentration-dependent manner, more potently to dopamine, but this effect is not related to direct binding at the uptake sites. It was also observed that a 3-day treatment with lipophilic extract prevents stress-induced corticosterone rise in mice frontal cortex but not in plasma. The lipophilic and methanolic H. caprifoliatum extracts also demonstrated antinociceptive effect, which seems to be indirectly mediated by the opioid system. These results indicate that H. caprifoliatum presents a promising antidepressant-like effect in rodents which seems to be related to a mechanism different from that of other classes of antidepressants. [source]


Norepinephrine Uptake Sites in the Locus Coeruleus of Rat Lines Selectively Bred for High and Low Alcohol Preference: A Quantitative Autoradiographic Binding Study Using [3H]-Tomoxetine

ALCOHOLISM, Issue 5 2000
Bang H. Hwang
Background: The locus coeruleus (LC) is the largest norepinephrinergic cell group in the central nervous system and contains a high density of norepinephrine (NE) uptake sites. Alcohol-preferring (AP) rats and high,alcohol-drinking (HAD) rats are selectively bred for high alcohol preference, whereas alcohol-nonpreferring (NP) rats and low,alcohol-drinking (LAD) rats are bred for low alcohol preference. However, it is unknown whether NE uptake sites in the LC are associated with alcohol preference in AP and HAD rats when compared with their respective control rats, NP and LAD rats. This study was designed to examine this question. Methods: Animals were decapitated and brains were removed, frozen with dry ice powder, and stored in a deep freezer. The LC tissue blocks were cut into 14 , cryostat sections, collected on glass slides, and incubated with 0.6 nM [3H]-tomoxetine in 50 mM Tris-HCl buffer system. For nonspecific binding, 1 ,M desipramine was added to the radioactive ligand. Sections were rinsed, quickly dried, and processed for quantitative autoradiography. In addition, galanin content in the LC was also studied. Results: The LC possessed a high density of [3H]-tomoxetine binding sites. There were fewer tomoxetine binding sites (fmol/mg protein) in the AP rats (433.0 ± 8.1) than in the NP rats (495.6 ± 3.7). HAD rats (386.5 ± 13.2) also possessed fewer tomoxetine binding sites than LAD rats (458.7 ± 10.1). Galanin content in the LC was similar between AP and NP rats and between HAD and LAD rats. Conclusions: Because both AP rats and HAD rats were selectively bred for alcohol preference, the finding of consistently low levels of [3H]-tomoxetine binding in the LC of these two lines of rats with high alcohol preference suggests that down-regulation of NE transporters in the LC of AP and HAD rats may be associated with alcohol-seeking behavior. A possible involvement of the coerulear NE uptake sites in depression is also discussed. Galanin in the LC may not relate to alcohol preference. [source]


Dopamine Transporter in vitro Binding and in vivo Imaging in the Brain

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2001
Kim A. Bergström
Recent findings indicate that dopamine reuptake is more like a highly regulated than a constitutive determinant of dopamine clearance. Positron emission tomography (PET) and single-photon emission tomography (SPET) offer unique methods to study dopamine transporter function. Results from in vivo PET and SPET studies correspond well with in vitro studies performed on post mortem human brain tissue. Considering some of the variances between in vitro and in vivo receptor binding phenomena it may be that the role of a compound to alter binding to monoamine uptake sites in vitro does not indicate its potential to affect monoamine transporters after administration in vivo. This discrepancy may be better understood taking into account recent studies indicating the possibility of a rapid regulation of transporter function and surface expression. Furthermore, the dopamine transporter is a fruitful target for CNS drug discovery. Fundamental nature of drug actions in vivo may be studied using demonstrated in vitro and in vivo imaging methods. [source]