Fig. 6.

Diffusion of NO from a fictive neuron being influenced by an NO sink at several time steps after the initiation of a 100 msec burst of synthesis. a, Position of the neuron and sink. The neuron is the large, annular body with several processes. The sink is the smaller elliptical shape near the cell body. b, Concentration profile 50 msec after the start of synthesis, i.e., during synthesis. c, Concentration profile 100 msec after the start of synthesis, i.e., at the end of synthesis. d, Concentration profile 150 msec after the start of synthesis.e, Concentration profile 250 msec after the start of synthesis. f, Concentration profile 750 msec after the start of synthesis. The heights in b–f denote the concentration and are shown as the fraction of peak concentration attained (6.32 μm). The x- and y -axis scales are in micrometers. Note the reservoir effect at the center of the large cell body. The NO sink causes a “shadow” behind it where the concentration is relatively low (f).