title: Calcium channel drugs affect nocturnal serotonin N-acetyltransferase (NAT) activity in rat pineal gland.
abstract: The effects of different organic compounds that block and increase Ca2+ influx through the voltage-sensitive calcium channels (VSCC) on the nocturnal serotonin N-acetyltransferase (NAT) activity was investigated in vivo in rats. Systemic administration of VSCC antagonists, i.e. nimodipine, nifedipine, verapamil and diltiazem, resulted in a marked suppression of the nighttime pineal NAT activity. Bay K 8644, a VSCC agonist, injected to rats before the time of the light offset of the light-dark cycle significantly enhanced the nocturnal increase of the pineal NAT activity. Although Bay K 8644 given during the dark phase of an imposed illumination cycle had little effect on the nocturnal pineal NAT activity, it antagonized the nimodipine- and verapamil-induced decrease in the enzyme activity. These results support the role of Ca2+ influx through the VSCC in the nocturnal increase of NAT activity in the pineal gland of rat.
authors.affiliation: Department of Pharmacodynamics, Polish Academy of Sciences, Lodz.
authors.forename: J B
authors.initials: JB
authors.lastname: Zawilska
authors.forename: J Z
authors.initials: JZ
authors.lastname: Nowak
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002940:Circadian Rhythm; D008297:Male; D008550:Melatonin / Q000096:biosynthesis; D010870:Pineal Gland / Q000187:drug effects* / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin; D002118:Calcium