LTP in Synapse

% FIGURE shows LTP in spine.
\RequirePackage{luatex85,shellesc}

\documentclass[crop]{standalone}

\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\usepackage{tikz}
\usetikzlibrary{positioning,calc,shapes,hobby}
\usetikzlibrary{scopes}
\usetikzlibrary{fit}
\usetikzlibrary{intersections, pgfplots.fillbetween}
\usetikzlibrary{arrows}

% Background layer.
\pgfdeclarelayer{bg}
\pgfdeclarelayer{ft}
\pgfsetlayers{bg,main,ft}

\renewcommand{\familydefault}{\sfdefault}
\pgfmathsetseed{10}

\input{structure}
\input{channel}

% Macros
\newcommand\VESICLE[3]{ % name, location, scale 
    \def\NODESIZE{1}
    \begin{scope}[shift={(#2)}]
        \node[circle,fill=white, inner sep=#3*\NODESIZE mm] (#1) at (0,0) {};
        \foreach \i in {1,...,5} {
            \pgfmathsetmacro\x{rand*\NODESIZE}
            \pgfmathsetmacro\y{rand*\NODESIZE}
            \node[fill=black!50, draw=none,circle,inner sep=0.7pt] at (\x mm,\y mm) {};
        }
    \end{scope}
}

\begin{document}


\begin{tikzpicture}[hobby]

    \SPINEWITHAXON{S1}{(-4,0)}{0.7}
    \SPINEWITHAXON{S2}{(4,0)}{1.2}

    % Now add some pre-synaptic vesicle
    \VESICLE{v1}{[yshift=0.75mm]S1_PRE_R2}{1}
    \VESICLE{v2}{[shift=(10:7mm)]v1}{1.2}
    \VESICLE{v3}{[shift=(180:4mm)]v1}{1}

    \VESICLE{v1}{[yshift=0.75mm]S2_PRE_R2}{1.2}
    \VESICLE{v2}{[shift=(20:7mm)]v1}{1.2}
    \VESICLE{v3}{[shift=(170:6mm)]v1}{1.2}

    \draw[-stealth, black, line width=1mm] (S1) to[] node[above] {\Large LTP} (S2);
    \draw[-stealth, gray, dashed, very thick] ([yshift=-4mm]S2.west) to[]
        ([yshift=-4mm]S1.east);

    % ADD RECEPTORS ON POST MEMBRANE.
    \CHANNEL{S1_SN1}{0.2}{0.1}{0}{black}{10}
    \CHANNEL{S1_SN2}{0.3}{0.2}{40}{blue}{0}
    \CHANNEL{S1_SN3}{0.2}{0.1}{30}{black}{-30}
    \CHANNEL{S1_SE1}{0.2}{0.1}{0}{black}{-60}

    \CHANNEL{S2_SN1}{0.2}{0.1}{0}{black}{10}
    \CHANNEL{S2_SN2}{0.3}{0.2}{40}{blue}{0}
    \CHANNEL{S2_SN3}{0.2}{0.1}{30}{black}{-30}
    \CHANNEL{S2_SE1}{0.2}{0.1}{0}{black}{-60}

    \coordinate (x1) at ([shift=(110:4mm)]S2_SE1);
    \coordinate (x2) at ([shift=(20:4mm)]S2_SN1);
    \coordinate (x3) at ([shift=(0:4mm)]S2_SN2);

    \CHANNEL{x1}{0.3}{0.2}{40}{blue}{-60}
    \CHANNEL{x2}{0.3}{0.2}{40}{blue}{10}
    \CHANNEL{x3}{0.2}{0.1}{0}{black}{-10}
    
\end{tikzpicture}	

\end{document}