S. Matsumura et K. Kuwasawa, BOTH THE HEART AND PERICARDIUM IN THE CHITON ACANTHOPLEURA-JAPONICA RECEIVE DUAL INNERVATION FROM THE CENTRAL-NERVOUS-SYSTEM, Zoological science, 13(1), 1996, pp. 55-62
The isolated heart or pericardium of the chiton Acanthopleura japonica
each showed rhythmic automaticity, even after they were isolated from
the body. Intracellular action potentials could be recorded from spon
taneously active myocardial cells in the isolated heart and pericardiu
m. They always appeared to be preceded by pacemaker potentials much as
has been found for myocardial cells of other molluscs. These show tha
t both heart and pericardial beats of Acanithopleura have a myogenic n
ature. Stimuli applied to each of the lateral and ventral nerve cords
produced both excitatory and inhibitory effects on the heart and the p
ericardium. Both the heart and the pericardium in Acanthopleura may re
ceive excitatory and inhibitory control from each of the lateral and v
entral nerve cords. The dual innervation of the heart which is seen co
mmonly in molluscs, at higher stages of evolution, may have been estab
lished in Acanthopleura at the stage of the phylogenetic beginning of
the Mollusca. On the contrary, the dual innervation which is required
for acceleratory and inhibitory control of the spontaneously rhythmica
lly active pericardium is different from the innervation seen in mollu
scs at the higher stages.