The effects of T-588, a novel cognitive enhancer, on noradrenaline uptake and release in rat cerebral cortical slices

Jpn J Pharmacol. 1998 Jun;77(2):155-60. doi: 10.1254/jjp.77.155.

Abstract

Previously, we reported that (R)-(-)-1-(benzo[b]thiophen-5-yl)-2-[2-(N,N-diethylamino)-ethoxy]e thanol hydrochloride (T-588), a novel cognitive enhancer, stimulated noradrenaline (NA) release from rat cerebral cortical slices. In this study, we investigated the effects of T-588 on NA uptake and release, compared to the effects of desipramine, a blocker of the NA carrier on the plasma membrane. Both T-588 and desipramine caused dose-dependent inhibition of [3H]NA uptake into the slices. Addition of 3 mM T-588 stimulated [3H]NA release from the prelabeled slices even in the presence of 10 microM desipramine, which inhibited NA uptake completely. Tyramine, which accelerates NA carrier-mediated release, also stimulated [3H]NA release, and tyramine-stimulated release was inhibited by desipramine. These findings indicated that T-588-stimulated NA release was not mediated by 1) inhibition of reuptake or 2) reverse transport mediated by NA carriers. Reserpine, which interacts with the intracellular vesicular transport system, increased [3H]NA efflux from slices. High K+-, not T-588-, stimulated [3H]NA release was shifted upward by reserpine. These findings suggest that T-588 evokes NA release by a mechanism similar to that induced by reserpine. T-588 might act as a cognitive enhancer via neurotransmitter release in the brain.

MeSH terms

  • Adrenergic Uptake Inhibitors / pharmacology
  • Animals
  • Calcium Chloride / pharmacology
  • Central Nervous System Stimulants / administration & dosage
  • Central Nervous System Stimulants / pharmacology*
  • Cerebral Cortex / drug effects*
  • Cerebral Cortex / metabolism*
  • Desipramine / pharmacology
  • Diethylamines / administration & dosage
  • Diethylamines / pharmacology*
  • Dose-Response Relationship, Drug
  • In Vitro Techniques
  • Male
  • Norepinephrine / metabolism*
  • Norepinephrine / pharmacokinetics*
  • Potassium Chloride / administration & dosage
  • Potassium Chloride / pharmacology
  • Rats
  • Rats, Wistar
  • Reserpine / administration & dosage
  • Reserpine / pharmacology
  • Thiophenes / administration & dosage
  • Thiophenes / pharmacology*
  • Tyramine / antagonists & inhibitors
  • Tyramine / pharmacology

Substances

  • Adrenergic Uptake Inhibitors
  • Central Nervous System Stimulants
  • Diethylamines
  • Thiophenes
  • T 588
  • Potassium Chloride
  • Reserpine
  • Calcium Chloride
  • Desipramine
  • Norepinephrine
  • Tyramine