Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Evidence ofr Calcium as the Spike Ion in Metridium senile
Student Author(s): Williams, David R.
Faculty Advisor(s): Fuhrman, Frederick
Pages: 21
Location: Final Papers Biology 175H
Date: June 1975
Keywords: sea anemones
Abstract: 1. There are two distinct types of stimulus site: one which responds to two pulses at low voltage, termed ideal, and the other which requires more pulses at higher voltage, termed non-ideal. 2. Stimulation at any site decrements the ability of the site to respond to further stimulation. 3. Nerve net initiated contractions may be differentiated from electrically initiated contractions. 4. Tetrodotoxin has no effect on the responses of Metridium senile to electrical stimulation. 5. Calcium-free sea water extinguishes response to electrical stimulation. 6. The presence of other divalent cations which are believed to compete with calcium extinguishes response. 7. It is theorized that calcium is the spike ion in the nervous system of M. senile.