(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 13. A model of the peptide actions on the excitatory transmission in the
vasoconstrictor muscle. AMRP acts mainly on the presynaptic receptors to
inhibit the excitatory transmitter release. Part of this inhibition is assumed
to be due to the activation of the 4-AP sensitive K+ channels.
Because 4-AP does not completely block the inhibitory action, other route to
inhibit the transmitter release seems to exist. Enterin activates both pre and
postsynaptic receptors. Activation of the postsynaptic receptors induces the
opening of the 4-AP sensitive K+ channels, and inhibits the
contraction. Because 4-AP does not completely inhibit the action of enterin,
the presynaptic inhibitory receptors are also assumed. NdWFamide also
activates both pre and postsynaptic receptors. Activation of the postsynaptic
receptors evokes the muscle contraction, and that of the presynaptic receptors
enhances the transmitter release.