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σ Receptor modulation of noradrenergic-stimulated pineal melatonin biosynthesis in rats
- Source :
- Scopus-Elsevier
-
Abstract
- Because sigma receptors are richly concentrated in the rat pineal gland, the present study was performed to investigate their possible role in the modulation of melatonin production. To this purpose, we assessed in vivo the effects of the sigma-receptor ligands 1,3-di(2-tolyl)guanidine and (+)-N-allylnormetazocine on the rat pineal gland activity during either the daytime or the nighttime. Compared with vehicle, 1,3-di(2-tolyl)guanidine and (+)-N-allylnormetazocine potentiated the enhancement of N-acetyltransferase activity and pineal melatonin content induced by isoproterenol administration during the daytime, whereas they did not affect the diurnal basal biosynthetic activity of the gland. Conversely, at night, 1,3-di(2-tolyl)guanidine and (+)-N-allylnormetazocine enhanced significantly the physiological increases in both pineal N-acetyltransferase activity and melatonin levels. This enhancement was prevented by pretreatment with rimcazole, a specific sigma-receptor antagonist. These findings suggest that, in rats, the activation of pineal sigma-receptor sites does not affect the biosynthetic activity of the pineal gland during daytime, whereas it potentiates the production of melatonin when the gland is noradrenergically stimulated either by isoproterenol administration or by the endogenously released norepinephrine at nighttime.
- Subjects :
- Male
endocrine system
medicine.medical_specialty
Rimcazole
Arylamine N-Acetyltransferase
Sigma receptor
n-acetyltransferase
Biology
Biochemistry
Guanidines
Pineal Gland
Melatonin
Cellular and Molecular Neuroscience
chemistry.chemical_compound
Pineal gland
Norepinephrine
Phenazocine
Internal medicine
medicine
Animals
Receptors, sigma
Circadian rhythm
Rats, Wistar
Sympathomimetics
Receptor
Isoproterenol
Aralkylamine N-acetyltransferase
Darkness
sigma receptors
Circadian Rhythm
Rats
Endocrinology
medicine.anatomical_structure
chemistry
melatonin
pineal gland
Catecholamine
Anticonvulsants
hormones, hormone substitutes, and hormone antagonists
medicine.drug
Antipsychotic Agents
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Scopus-Elsevier
- Accession number :
- edsair.doi.dedup.....126acf985786bb3af8f8e63b5c776be0