Home
Resources
Publications
In-vivo Microdialysis Measurement of 5-hydroxytryptamine and Its Metabolites, 5-hydroxyindoleacetic Acid and N-acetyl 5-hydroxytryptamine, in Rat Blood: Effects of Histamine-Receptor Antagonists

In-vivo Microdialysis Measurement of 5-hydroxytryptamine and Its Metabolites, 5-hydroxyindoleacetic Acid and N-acetyl 5-hydroxytryptamine, in Rat Blood: Effects of Histamine-Receptor Antagonists

E Sakurai, A Monura, J Yamakami, N Hikichi

J Pharm Pharmacol. 1996 Sep;48(9):911-3.

PMID: 8910852

Abstract:

The blood concentrations of 5-hydroxytryptamine (5-HT) and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA) and N-acetyl 5-HT were assayed by in-vivo microdialysis and a highly sensitive HPLC procedure that was originally developed to analyse CNS mediators. We investigated the effects of histamine-receptor antagonists on 5-HT metabolism and its release into the blood of rats. The mean basal levels of 5-HT, 5-HIAA and N-acetyl 5-HT in the blood measured by in-vivo microdialysis were 77.2 +/- 9.4, 20.3 +/- 1.5 and 1.89 +/- 0.15 pmol mL-1, respectively. These levels were not significantly affected by an intraperitoneal injection of saline, and remained at constant levels for at least 8 h after administration of saline. After an intraperitoneal injection of 5-HT hydrochloride (0.5 mg kg-1), 5-HT was soon detected in the blood of the jugular vein. 5-HIAA also quickly appeared in the blood and declined monoexponentially from 60 min after injection. In contrast, N-acetyl 5-HT slowly appeared in the blood and it reached a maximal level at 270 min. The 5-HT and N-acetyl 5-HT levels in dialysates from rat jugular vein were significantly increased by intraperitoneal pyrilamine (2.0 mg kg-1), (+)-chlorpheniramine (2.0 mg kg-1) and cimetidine (20.0 mg kg-1). However, there was no increase in the 5-HIAA concentration after an intraperitoneal injection of these histamine-receptor antagonists, demonstrating that the 5-HT released from various cells containing 5-HT was predominantly metabolized to N-acetyl 5-HT by N-acetyltransferase. Moreover, thioperamide did not affect the basal levels of 5-HT, 5-HIAA or N-acetyl 5-HT. Because the recovered 5-HT, 5-HIAA and N-acetyl 5-HT in the dialysate is directly proportional to the free fraction in the blood, in-vivo microdialysis is a reliable method of examining 5-HT metabolism and its release into the blood.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP1210839	N-Acetyl-5-hydroxytryptamine		1210-83-9	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: