ISSN:
0095-9898
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The effects of continuous darkness and abnormal ionic ratios (excess Ca+ +, Mg+ +, K+, and absence of Na+) on the fine structure of the rhabdoms and on the intracellular retinal receptor potentials were studied in crayfish compound eyes. The normal rhabdom has its constituent microvilli regularly arranged in a characteristic cross-banded pattern. The normal retinular cell response consists of an initial transient peak and a sustained plateau. After the crayfish were kept for three months in the dark, the regular arrangement of rhabdom microvilli was markedly upset, and receptor potentials of retinular cells in the eye consisted only of the slow phase. The initial phase of the intracellular retinal receptor potential is more labile than the sustained phase (plateau) and was easily abolished if the rhabdom was so strongly affected by continuous darkness, excess Ca+ +, and excess K+ that the fine structural arrangements of microtubules were destroyed. Since receptor potentials were recorded from compound eyes in which rhabdoms were deranged and almost all their microvilli torn off from the retinular cells, transmission of visual excitation from rhabdom to retinular cell soma must be possible without direct membranous connection between them.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1030660314
