Drugs online research references
Br J Pharmacol. 1998 Oct;125(3):526-32.
Blockade of 5-hydroxytryptamine and noradrenaline uptake by venlafaxine: a comparative study with paroxetine and desipramine.
Beique JC, de Montigny C, Blier P, Debonnel G.
Neurobiological Psychiatry Unit, McGill University, Montreal, Canada.
1. Venlafaxine is an antidepressant agent which blocks in vitro the reuptake of both 5-HT and NA. The present in vivo electrophysiological studies were undertaken, in the rat, to compare the effects of venlafaxine on 5-HT and NA reuptake to those of the selective 5-HT reuptake inhibitor paroxetine and the selective NA reuptake inhibitor desipramine. 2. Administered acutely, venlafaxine dose-dependently prolonged the time required for a 50% recovery (RT50) of the firing activity of dorsal hippocampus CA3 pyramidal neurons from the suppression induced by microiontophoretic applications of 5-HT and NA. Venlafaxine and paroxetine increased with a similar potency the RT50 values for 5-HT, while desipramine was more potent than venlafaxine at increasing the RT50 values for NA. Moreover, venlafaxine demonstrated a greater potency at increasing the RT50 values for 5-HT compared to that of NA. 3. A two-day treatment with venlafaxine (delivered s.c. by osmotic minipumps) increased the RT50 values for both 5-HT and NA applications. The RT50 values for 5-HT were significantly increased at a dose of 10 mg kg(-1) day(-1), whereas those for NA were increased at a dose of 20 mg kg(-1) day(-1), consistent with the data obtained following the acute administration of venlafaxine. 4. Taken together, these results indicate that, in vivo, venlafaxine blocks both reuptake processes, with a potency greater for the 5-HT than for the NA reuptake process. This dual action, combined with the differential potency of venlafaxine, might constitute the biological substratum responsible for its apparent unique clinical efficacy in major depression.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9806336&dopt=Abstract
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Am J Physiol. 1998 Dec;275(6 Pt 1):C1621-9.
Relationship between [125I]RTI-55-labeled cocaine binding sites and the serotonin transporter in rat placenta.
Shearman LP, McReynolds AM, Zhou FC, Meyer JS.
Department of Psychology, Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts 01003, USA.
We investigated the characteristics of cocainelike binding sites in rat placenta using [125I]RTI-55. [3H]paroxetine binding and immunocytochemical staining for serotonin [5-hydroxytryptamine (5-HT)] and for the 5-HT transporter were also used to obtain evidence for rat placental 5-HT uptake. [125I]RTI-55 saturation analyses with membranes from normal gestational day 20 placentas yielded curvilinear Scatchard plots that were resolved into high- and low-affinity components (mean dissociation constants of 0.29 and 7.9 nM, respectively). Drug competition studies with various monoamine uptake inhibitors gave rise to complex multiphasic displacement curves, although the results obtained with the selective 5-HT uptake inhibitor citalopram suggest that the 5-HT transporter is an important component of placental high-affinity [125I]RTI-55 binding. The presence of a rat placental 5-HT uptake system was additionally supported by the [3H]paroxetine binding experiments and by the presence throughout the placenta of immunoreactivity for 5-HT and the 5-HT transporter. Immunostaining with both antibodies was most intense in the junctional zone, whereas the density of [125I]RTI-55 binding sites was greater in the placental labyrinth. This discrepancy may be due to the fact that [125I]RTI-55 appears to be labeling additional cellular components besides the 5-HT transporter. The presence of cocaine- and antidepressant-sensitive 5-HT transporters in the placenta has important implications for the possible effects of these compounds on pregnancy and fetal development.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9843724&dopt=Abstract
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J Pharm Biomed Anal. 1999 Apr;19(5):793-802.
Method development and validation for the HPLC assay (potency and related substances) for 20 mg paroxetine tablets.
Lambropoulos J, Spanos GA, Lazaridis NV.
Analytical Method Development and Validation, AAI, Inc., Wilmington, NC 28405, USA.
A reversed phase high performance liquid chromatographic (HPLC) method was developed and validated for use as a stability indicating assay (potency and related substances) of paroxetine in paroxetine hydrochloride 20 mg tablets. Assay samples were extracted at a paroxetine concentration of 0.4 mg ml(-1) utilizing mobile phase as the extraction solvent. The chromatographic conditions employed a C18 column (Inertsil, 5 microm, 15 cm x 4.6 mm), isocratic elution with 10 mM 1-decane sulfonic acid sodium salt containing 10 mM sodium phosphate monobasic (pH 3.0)-ACN (60:40, v/v) and ultraviolet (UV) detection at 235 nm.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10698543&dopt=Abstract
note: kwd match paxil online literature
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