Fig. 2. Schematic neuron—enlargement of  figure 1B . Dendrite (  upper left ) receives chemical/neurotransmitter synapse from incoming axon. Enlarged view (  circle, left ) shows postsynaptic receptors and cytoskeletal structures in dendritic spine. Actin filaments in spine link to microtubules in main dendrite. Dendrite (  upper right ) connected by gap junction to dendrite of another neuron. Enlarged view (  circle, right ) shows gap junction window-like opening formed by collar of connexin protein. Cytoskeletal microtubules interconnected by microtubule-associated proteins are also shown in both dendrites. Anesthetics act primarily on dendritic receptors, channels, and cytoskeletal structures.