[The ultrastructure of desmosome-like contacts in mixed synapses of Mauthner cells followed long-term potentiation].

Using electron microscopic morphometry, the effect of long-term potentiation on the structure of transverse fibrillar bridges localized in a cleft of desmosome-like contacts in mixed synapses of goldfish Mauthner neurons, was studied. The number of bridges was shown to increase with the augmentation of the potentiation level of electrotonic conductivity. In contrast to control (incubation), the structure of bridges was also changed after potentiation. The paired bridges appeared that could have an arrangement within the cleft different from that one in control. On the basis of the present results in conjunction with earlier findings, the possible actin nature of these bridges was suggested. The bridge seems to represent a channel containing actin, arranged in a pattern similar to that one in nanotubules or plasmodesmas, what can, possibly, explain the stability of bridge structure observed after application of [symbol: see text] D and other extrinsic damaging factors.