Biomaterial Database

The Retzius cells in the leech: a review of their properties and synaptic connections. 1988

M Carretta

Institute of Human Physiology, Perugia, Italy.

1. The Retzius cells (RCs) project an axonal branch in each anterior, posterior and dorsal segmental root. 2. RCs are the only serotonin-containing neurons projecting to the periphery. 3. RCs are activated by mechano-sensory neurons, by serotonin-containing neurons and by two pairs of subesophageal neurons, Tr 1 and Tr 2. 4. RCs also receive an excitatory and an inhibitory input from sensilla. 5. These inputs could form two systems, one converging onto RCs of each ganglion and one distributing to other ganglia after processing by RCs. 6. RCs play a role in muscle tension, in mucous release and in swimming activity.

UI	MeSH Term	Description	Entries
D007865	Leeches	Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.	Hirudinea,Hirudineas,Leeche
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse