Abstract
The effect of pituitary adenylate cyclase polypeptide (PACAP) on rat pineal was examined. PACAP stimulated melatonin release from cultured dissociated pinealocytes with a 10(4) higher potency than isoproterenol (EC50 were 30 pM and 250 nM, respectively). The 10(-9) M PACAP stimulation was not inhibited by 5 x 10(-6) M VIP antagonist whereas that of 10(-9) M VIP was reduced by 54%. Kinetic analysis of melatonin release indicated that PACAP acts postsynaptically via receptor activation.
MeSH terms
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Animals
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Cells, Cultured
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In Vitro Techniques
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Isoproterenol / pharmacology
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Male
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Melatonin / biosynthesis*
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Neuropeptides / pharmacology*
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Neurotransmitter Agents / pharmacology*
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Perfusion
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Pineal Gland / drug effects
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Pineal Gland / metabolism*
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Pituitary Adenylate Cyclase-Activating Polypeptide
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Rats
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Rats, Wistar
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Receptors, Gastrointestinal Hormone / antagonists & inhibitors
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Receptors, Vasoactive Intestinal Peptide
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Stimulation, Chemical
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Vasoactive Intestinal Peptide / antagonists & inhibitors
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Vasoactive Intestinal Peptide / pharmacology
Substances
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Adcyap1 protein, rat
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Neuropeptides
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Neurotransmitter Agents
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Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Gastrointestinal Hormone
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Receptors, Vasoactive Intestinal Peptide
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Vasoactive Intestinal Peptide
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Melatonin
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Isoproterenol