Enhanced serotonergic neurotransmission in the hippocampus following tryptophan administration improves learning acquisition and memory consolidation in rats.
Journal Title: Pharmacological Reports - Year 2007, Vol 59, Issue 1
Abstract
Increasing evidence shows that serotonin (5-hydroxytryptamine - 5-HT) plays a modulatory role in memory functions. 5-HT transmission has been implicated in learning and memory. Both 5-HT depletion and specific 5-HT agonists lower memory performance. Hippocampus is thought to be the key region involved in long-term memory. It is the major limbic target of the brainstem serotonergic neurons that modulate learning. In the present study, we examined the effects of increased hippocampal 5-HT metabolism following tryptophan (TRP) administration on short-term memory (STM) and long-term memory (LTM) in rats. Learning acquisition (LA) and memory consolidation (MC) in rats was also evaluated. TRP at 50 mg/kg and 100 mg/kg body weight was used. Assessment of memory in rats was done using the water maze test (WM) after 6 weeks of daily administration of TRP. The results showed that administration of TRP enhanced both STM and LTM. However, the effect on STM was significant only at the higher dose. Rats administered the higher dose of TRP also exhibited a significant enhancement in LA. A significant effect on MC was also observed in tryptophan-treated rats. The results suggest that serotonergic system in the hippocampus is important in LA and MC in rats.
Authors and Affiliations
Saida Haider, Saima Khaliq, Darakhshan Haleem
Keywords
Related Articles
- EP ID EP128855
- DOI -
- Views 64
- Downloads 0
Anti-hypertensive effects of probenecid via inhibition of the α-adrenergic receptor.
Probenecid has long been used in the treatment of gout. Its anti-gout mechanisms consist of uric acid reuptake inhibition and the consequent facilitation of uric acid excretion. In the present study, we investigated whet...
Effects of amiloride and bumetanide on hyperpolarization after movement across the distal colon epithelium.
The aim of the paper was to define which transepithelial ion transport pathways were activated during stimulation by movement across the colonic epithelium. The experiments were performed with Ussing method on 241 specim...
Lack of effect of some dopamine and non-dopamine receptor ligands on amphetamine-induced changes in the rat brain neuropeptide Y system.
None of the receptor ligands studied: the dopamine D(2) antagonist eticlopride, D(2)/D(3) antagonist haloperidol, alpha(1)-adrenergic antagonist prazosin, N-methyl-D-aspartate antagonist MK-801, 5-HT(2)/D(2) antagonist m...
Pharmacokinetics and metabolism of nicotine.
Nicotine (NIC), the major constituent of tobacco, is responsible for the compulsive use of tobacco. Advances in understanding of the pharmacokinetics and metabolism of NIC have been made rapidly over the past decade. The...
D-serine, a selective glycine/N-methyl-D-aspartate receptor agonist, antagonizes the antidepressant-like effects of magnesium and zinc in mice.
Zinc and magnesium are potent inhibitors of the N-methyl-D-aspartate (NMDA) receptor complex. Recent data demonstrate that both zinc and magnesium, like other NMDA receptor antagonists, exhibit antidepressant-like activi...