Psychological and physiological effects of nitrous oxide resemble those of eight other drug categories. Lipid solubility or hydrate microcrystal theories correlate behavioral measures with measurable parameters of the molecule N20. N20, a spindle poison, halts mitosis in metaphase, producing widespread physiological consequences. N20 affects the microtubules of the spindle in a number of specific ways. Microtubules are utilized in other parts of eukaryotic cells, in a wide variety of functions. In neurons, microtubules build and maintain dendritic sensory processes. Since microtubules are built of two dissimilar proteins, constantly assemble and disassemble, and maintain a more negative interior potential, they would be responsive to changes in summed post-synaptic dendritic potential. Microtubules respond to N20 with a loss of communication between subcellular components, and between cells. Chromosomes, proteins, and ATP are no longer transported efficiently. Such fundamental changes might explain nitrous oxide's effects in "potentiating" other drugs, and upon perception and memory.