The effects of the tubulin-binding drug, colchicine, on the electrophysiological aspects of phototransduction in toad rod photoreceptors

Colchicine, known for its antimitotic properties, its effects on neuronal conductances and its use as a treatment for acute gout, was found to affect phototransduction in toad rods during pharmacologic screening of cytoskeletal antagonists. Colchicine superfusion onto intact retinas hyperpolarized rods, increased their membrane resistance and altered the kinetics of voltage responses to light flashes. These effects persisted during blockade of rod inner segment conductances, but colchicine's effects during illumination were minimal. The presence of colchicine, however, did not block rod depolarization evoked by increasing intracellular 3$\sp\prime$,5$\sp\prime$-cyclic guanosine monophosphate, cGMP (the physiologic activator of the light-sensitive conductance, g$\sb{\rm h\nu}$), either physiologically or exogenously. It was concluded that colchicine blocks the light-sensitive current, probably by lowering (cGMP) $\sb{\rm i}$ rather than by acting as a cGMP antagonist at the channel.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Bert, Robert James

Contributors dc:contributor

• Oakley, Burks, II

• Biology, Neuroscience
• Biology, Animal Physiology
• Biophysics, General

Statement dc:rights

• Copyright 1990 Bert, Robert James

Language dc:language

eng

Identifier

AAI9114176
(UMI)AAI9114176

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20601