In vitro effects of putative neurotransmitters on synaptic ribbon numbers and N-acetyltransferase activity in the rat pineal gland

• Published in: Journal of Neural Transmission Vol. 89; no. 3; pp. 167 - 178
• Main Authors: GUPTA, B. B. P, SEIDEL, A, SPESSERT, R, BÜTTNER, W, KLAUKE, N, SPANIER, J, WEBER, A, ZIEMER, D, VOLLRATH, L
• Format: Journal Article
• Language: English
• Published: Wien Springer 01-10-1992; New York, NY
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Morphology. Functional localizations; Vertebrates: endocrinology; Endocrine gland; Rat; Enzyme; Rodentia; Neuroendocrine regulation; Pineal body; Synaptic ribbon; Circadian rhythm; Neuropeptide; Vertebrata; Synapse; Mammalia; Enzymatic activity; Ultrastructure; Neuromediator; Arylamine acetyltransferase
• ISSN: 0300-9564; 1435-1463
• DOI: 10.1007/BF01250669

We have investigated in vitro effects of a number of classical neurotransmitters and neuropeptides. NAT activity was used to monitor melatonin synthesis under the experimental conditions used. Norepinephrine (NE), Delta sleep-inducing peptide (DSIP), vasoactive intestinal polypeptide (VIP), adenosine and N-acetyl-asp-glu (NAAG) significantly increased NAT activity in rat pineal. DSIP and VIP also increase the stimulatory effect of NE on NAT activity. These neurochemicals had no effect on SR numbers. Gamma aminobutyric acid (GABA), serotonin and taurine affected neither NAT activity nor SR. Somatostatin increased SR numbers significantly, without having any effect on NAT activity. The effect of somatostatin is regarded to be pharmacologic, since rather high dosages were required to obtain a significant effect.