International E-publication: Publish Projects, Dissertation, Theses, Books, Souvenir, Conference Proceeding with ISBN.  International E-Bulletin: Information/News regarding: Academics and Research

An in vitro study on the role of protein kinase C, phosphodiesterase and Ser/Thr phosphatases in adrenergic stimulation of arylalkylamine-N-acetyltransferase (AA-NAT) activity in the pineal gland of Clariasgariepinus

Author Affiliations

  • 1Department of Zoology, Lady Keane College, Shillong-793 001, India
  • 2Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793 022, India

Int. Res. J. Biological Sci., Volume 5, Issue (12), Pages 18-23, December,10 (2016)


The effects of inhibitors of PKC, PDE and ser/thr phosphatase 1, 2A and 2B on the activity of arylalklyamine N-acetyltransferase (AA-NAT) was studied in vitro in the pineal glands of the catfish, Clariasgariepinus.Pineals were pre-treated with specific inhibitors prior induction by norepinephrine then maintained in organ culture for 7 hr. In vitro treatment of the fish pineal organ with chelerythrine (PKC inhibitor) significantly decreased AA-NAT activity as compared to that of the control group. Theophylline (PDE inhibitor) treated at different incubation periods significantly increased AA-NAT activity. Okadaic acid (inhibitor of ser/thr phosphatase 1) and calyculin A (inhibitor of ser/thr phosphatase 2A) significantly inhibited basal AA-NAT activity. Cypermethrin (inhibitor of ser/thr phosphatase 1) show no significant effect neither on basal AA-NAT activity nor on NE-induced increased in the enzyme activity. These results suggest that PKC does not seem to be involved in adrenergic stimulation but necessary for maintaining basal activity of the enzyme. PDE also crucially regulate the activity of the AA-NAT enzyme. The normal as well as the adrenergic stimulation of AA-NAT by Ser/Thr phosphatase 1 and 2A are essential, but, Ser/Thr phosphatases 2B do not play any major part in adrenergic signal transduction in the fish pinealocytes.


  1. Gupta B.B.P., Spessert R. and Vollrath L. (2005)., Molecular components and mechanism of adrenergic signal transduction in mammalian pineal gland: Regulation of melatonin synthesis., Indian J. Exp. Biol., 43, 115-149.
  2. Vanecek J., Sugden D., Weller J. and Klein D.C. (1985)., Atypical synergistic α1-and b-adrenergic regulations of adenosine 3, 5-monophosphate and guanosine 3, 5-monophosphate in rat pinealocytes., Endrocrinol., 116, 2167-2173.
  3. Vanecek J., Sugden D., Weller J.L. and Klein D.C. (1986)., See-saw signal processing in pinealocytes involves reciprocal changes in the 1-adrenergic component of the cyclic GMP response and the -adrenergic component of the cAMP responses., J. Neurochem., 47, 678-686.
  4. Chik C.L. and Ho A.K. (1989)., Multiple receptor regulation of cyclic nucleotides in rat pinealocytes., Proc. Biophys. Mol. Biol., 53, 197-203.
  5. Zawilska J.B., Rosiak J. and Nowak J.Z. (1998)., Cascade of biochemical events triggered by stimulation of adrenergic receptors in the rat pineal gland--from cell membrane to nucleus., Postepy. Hig. Med. Dosw., 53(2), 233-246.
  6. Ho A.K., Chik C.L. and Klein D.C. (1987)., Protein kinase C is involved in adrenergic stimulation of pineal cGMP accumulation., J. Biol. Chem., 262, 10059-10064.
  7. Schomerus C., Laedtke E., Olcese J., Weller J.L., Klein D.C. and Korf H.W. (2002)., Signal transduction and regulation of melatonin synthesis in bovine pinealocytes: impact of adrenergic, peptidergic and cholinergic stimuli., Cell Tiss. Res., 309, 417-428.
  8. Abdel-Latif A.A. (1986)., Calcium-mobilizing receptors, polyphosphoinositides, and the generation of second messengers., Pharmacol. Rev., 38, 227-272.
  9. Choi B.H., Chae H.D., Park T.J., Oh J., Lim J., Kang S.S.H. and Kim K.T. (2004)., Protein kinase C regulates the activity and stability of serotonin N-acetyltransferase., J. Neurochem., 90, 442-454.
  10. Kim T.D., Kim J.S., Kim J.H., Myung J., Chae H.D., Woo K.C., Jang S.K., Koh D.S. and Kim K.T. (2005)., Rhythmic Serotonin N-Acetyltransferase mRNA Degradation Is Essential for the Maintenance of Its Circadian Oscillation., Mol. cellular Biol., 25, 3232-3246.
  11. Klein D.C., Coon S.L., Roseboom P.H., Weller J.L., Bernard M., Gastel J.A., Zatz M., Iuvone P.M., Rodriguez, I.R., Begay V., Falcon J., Cahill G.M., Cassone V.M. and Baler R. (1997)., The melatonin rhythm generating enzyme: molecular regulation of serotonin N-acetyltransferase in the pineal gland., Recent Prog. Horm. Res., 52, 307-358.
  12. Fukuhara C., Yamazaki S. and Liang J. (2005)., Pineal circadian clocks gate arylalkylamine N-acetyltransferase gene expression in the mouse pineal gland., J. Neurochem., 93, 156-162.
  13. Morin F., Lugnier C., Kameni J. and Voisin P. (2001)., Expression and role of phosphodiesterase 6 in the chicken pineal gland., J. Neurochem., 78(1), 88-99.
  14. Spessert R., Rapp M., Jastrow H., Karabul N., Blum F. and Vollrath L. ( 2000)., A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal., Brain Res., 864, 270-280.
  15. Spessert R., Rapp M. and Vollrath L. (2001)., Serine/Threonine Phosphatase Inhibitors Decrease Adrenergic Arylalkylamine N-Acetyltransferase Induction in the Rat Pineal Gland., J. Neuroendocrinol., 13, 581-587.
  16. Hunter T. (1995)., Protein kinases and phosphatases: the yin and yang of protein phosphorylation and signaling., Cell, 80, 225-236.
  17. Stehle J.H., Von Gall C., Schomerus C. and Korf H.W. (2001)., Of rodents and ungulates and melatonin: creating a uniform code for darkness by different signaling mechanisms., J. Biol. Rhythms, 16(4), 312-325.
  18. Olcese J. (2003)., Circadian signaling in the chick pineal organ., Chronobiol. Int., 20(4), 617-636.
  19. Premabati Y. (2005)., Study of thyroid-pineal relationship in the fish, Clariasgariepinus., Ph. D thesis, North Eastern Hill University, Shillong.
  20. Deguchi T. and Axelrod J. (1972)., Sensitive assay for N-acetyltransferase activity in rat pineal gland., Anal. Biochem., 50, 174-179.
  21. Olivieri G. and Daya S. (1992)., Adenosine 5, J. Pineal Res., 12(2), 53-57.
  22. Zurawska E. and Nowak J.Z. (1991)., Serotonin N-acetyltransferase (NAT) induction in mammalian retina: role of cyclic AMP and calcium ions., Folia Histochem. Cytobiol., 30, 5-11.