Sep 1, 1976

Propagated spikes and secretion in a coelenterate glandular epithelium

The Journal of General Physiology
G O Mackie

Abstract

The rete mirabile of Hippopodius (Cl. Hydrozoa, O. Siphonophora) is a sheet of giant endoderm cells penetrated by branches of the ventral radial canal. The cells appear to be highly polyploid. The rough ER is very richly developed and expanded ER cisternae containing amorphous material (presumably synthesized protein) are observed near the outer cell surface. The cells are electrically coupled, and are connected by gap junctions. The rete is electrically excitable and cell to cell conduction of action potentials at 10 cm/s is observed. The action potentials are all-or-none, positive-going events, showing amplitudes of about 70 mV and arising from a 44 mV resting potential. Slowly developing and decaying secondary depolarizations, capable of summing to the 20 mV level, are also observed. After passage of a train of impulses, the rete cells swell and secretion drops appear at the surface, these changes becoming apparent within a few seconds. In 15 mM Mn2+ the response fails to occur, and secondary depolarizations ("secretion potentials") are not seen. Spike propagation is not affected. In Na+-free solutions the spikes are reduced and propagation eventually fails. It is suggested that the spikes are sodium-dependent events which t...Continue Reading

  • References
  • Citations10

References

  • We're still populating references for this paper, please check back later.

Mentioned in this Paper

Endoderm
Manganese
Calcium [EPC]
Calcium
Secretory Pathway
Glandular Epithelium
Resting Potentials
Action Potentials
Hippopodius
Process of Secretion

About this Paper

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.