“…The destruction of microtubules by colchicine and vinblastin may be associated with an increase in the number of neurofilaments (Wisniewski, Terry & Hirano, 1970); hence, axonal flow may be blocked either by the destruction of microtubules or by the increased numbers of neurofilaments (Fink et al 1973;Byers, Fink, Kennedy, Middaugh & Hendrickson, 1974) or by the blocking of the oxidative metabolism by lidocaine, an agent frequently used in these experiments (Cullen & Haschke, 1974;Sakabe, Maekawa, Ishikawa & Takeshita, 1974;Novotny & Bianchi, 1967). Our data indicate that the increase in neurofilaments is independent of the destruction of microtubules (Table 2).…”