Neural network regulating heart activity in Aplysia depilans and its comparison with other gastropod species

Abstract

1. 1. The efferent part of heart regulatory neural network was investigated in Aptysia depilans. 2. 2. In the abdominal ganglion 9 identified giant neurons and 12 unidentified small cells were found which modified heart activity, 3 neurons of the RP1G. 1-1 cell of the RPG and LPG involved in heart regulation were also detected. 3. 3. Similar to other gastropod species, the heart regulatory neural network of Aplysia depilans is scattered throughout the CNS. 4. 4. Most of the neurons having efferent influences on the heart receive also inputs from heart. There were only six exceptions, five located in the abdominal ganglion and one in the LPG. A left side dominancy was found in the localization of heart regulatory neurons. 5. 5. One interneurone (L10) and two motoneurons (RB HE, LD HI 1 ) were identified and described earlier in other Aplysia species. Cell L10 was silent or displayed tonically active or a bursting pattern. Its tonic firing led to the inhibition of the heart. Neurone L10 received indirect information from the heart. 6. 6. There exist mutual connections between or similar inputs in neurones located in different ganglia. The regulation of heart activity in Aplysia depilans seems to be accomplished by the aid of multifunctional neural networks, where the regulation of various organs is subordinated to the need of the whole organism.