The stomatogastric nervous system of the medicinal leech: its anatomy, physiology and associated aminergic neurons.

Blood feeding is an essential and signature activity of the medicinal leech species . Despite keen interest in understanding the neuronal substrates of this behavior, a major component of the nervous system associated with feeding has remained overlooked. In this study, for the first time, we report on the presence and characteristics of five stomatogastric ganglia (STGs) comprising the visceral stomatogastric nervous system (STN) of the leech.

Higher-order control of the feeding network in Lymnaea.

A novel excitatory higher-order input (named Input-HO) to the feeding network of the pond snail, Lymnaea stagnalis, as well as a reliable procedure that makes it possible to initiate and maintain the Input-HO, are described. The Input-HO is primarily targeted to two bilaterally symmetrical pairs of extrabuccal projecting interneurons, the serotonergic Cerebral Giant Cells (CGCs or C1) and FMRFamidergic Pleural-Buccal cells (PlBs). Judging from the results of transection experiments, Input-HO originates in the paired cerebral ganglia where its left and right sources coexist.

Hyperpolarization by glucose of feeding-related neurons in snail.

In the pond snail Lymnaea stagnalis, D-glucose action was investigated on electrical activity of identified central neurons. In the CNS preparations isolated from specimens that starved for 24-96 h, D-glucose added to a standard or HiDi saline at 500-700 microg/ml effectively hyperpolarized ca. 90% of feeding related neurons B1, SO and CGC.