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Involvement of protein kinase C in 5‐HT‐stimulated ciliary activity in Helisoma trivolvis embryos
Author(s) -
Christopher Kimberley J.,
Young Kevin G.,
Chang John P.,
Goldberg Jeffrey I.
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.511ac.x
Subject(s) - protein kinase c , bisindolylmaleimide , diacylglycerol kinase , phorbol , calphostin c , biology , tetradecanoylphorbol acetate , medicine , chemistry , endocrinology , biophysics , microbiology and biotechnology , kinase
1 During development, embryos of the pulmonate gastropod, Helisoma trivolvis , undergo a rotation behaviour due to the co‐ordinated beating of three bands of ciliated epithelial cells. This behaviour is in part mediated by the neurotransmitter serotonin (5‐HT) released from a pair of identified embryonic neurons. Using time‐lapse videomicroscopy to measure ciliary beat frequency (CBF) in response to pharmacological manipulations, we determined whether protein kinase C (PKC) is involved in mediating 5‐HT‐stimulated ciliary beating. 2 Diacylglycerol (DAG) analogues sn ‐1,2‐dioctanoyl glycerol (DiC 8 ; 100 μM) and 1‐oleoyl‐2‐acetyl‐ sn ‐glycerol (OAG; 100 μM), partially mimicked the 5‐HT‐induced increase in CBF. In contrast, application of OAG in the absence of extracellular Ca 2+ did not result in an increase in CBF. 3 5‐HT‐stimulated CBF was effectively blocked by PKC inhibitors bisindolylmaleimide (10 and 100 nM) and calphostin C (10 nM). In addition, bisindolylmaleimide (100 nM) inhibited DiC 8 ‐induced increases in CBF. At a higher concentration (200 nM), bisindolylmaleimide did not significantly reduce 5‐HT‐stimulated cilio‐excitation. 4 Two different phorbol esters, phorbol 12‐myristate 13‐acetate (TPA; 0.1, 10 or 1000 nM) and phorbol 12β, 13α‐dibenzoate (PDBn; 10 μM) did not alter basal CBF. TPA (1 μM) did not alter 5‐HT‐stimulated CBF. Likewise, the synthetic form of phosphatidylserine, N ‐(6‐phenylhexyl)‐5‐chloro‐1‐naphthalenesulphonamide (SC‐9; 10 μM), did not increase CBF, whereas a strong increase in CBF was observed upon exposure to 5‐HT. 5 The results suggest that a DAG‐dependent, phorbol ester‐insensitive isoform of PKC mediates 5‐HT‐stimulated CBF in ciliated epithelial cells from embryos of Helisoma trivolvis .