Axonal microtubules: a computer-linked quantitative analysis.

Employing current computer-aided morphometric techniques, axonal microtubule density was determined for the rat sural nerve. Analysis of extensive data showed that while microtubule number increases with axon size, the increase is not directly proportional. Thus the relationship between microtubule density and axonal size is inversely related, so that microtubule density is greater in smaller axons than in larger axons. When a proximal and distal site, separated by 2 cm, were compared for microtubule density there was no significant difference, using pooled data for all fibre diameters. The results are interpreted in terms of our present knowledge of axonal-microtubule quantitative relationships, which is reviewed.