L/RPeD11 are neurons in Lymnaea stagnate.
Left and right pedal dorsal 11 (L/RPeD11) neurons are a pair of bilateral internerons that form electrical connections with the foot and body wall of the Lymnaea stagnate. They coordinate locomotor motoneurons and play a key role in whole-body withdrawal. They are also involved in regulating respiratory behavior through chemical connections with heart motoneurons.
|The L/RPeDll neurons are located on the dorsal surface of the left and right pedal ganglia, respectively, with cell bodies located at the pedal end of in front of the statocyst. They are electrically coupled to each other and have similar structures. They are the largest cells in the pedal G clusters with cell bodies measuring 30-50/an in diameter. They encircle the lower ganglionic ring and enter the cerebral ganglia.
Projections from L/RPeD11 have branches in many ganglia, i.e. pedal, pleural, parietal and visceral. Extensive axonal arborizations of LPeDll and RPeDll are found in neuropile areas where somata or axonal branches of L/RPeG cluster and where visceral H, I, J and K cells are located.
LPeDll has two main axons, one running ipsilaterally and the other contralaterally, which have 3 projections:
RPeD11 projects to the periphery via:
|Electrical Connections |
L/RPeDll are electrically coupled to each other and to locomotor and body wall motoneurones:
The L/RPeD11 neurons are critical in the survival of the Lymnaea as they synchronize contraction of body wall and foot muscles with cessation of locomotion and respiratory activity during the animal’s escape response. This multifunctional role involves (1) coordinating motor behavior involved in whole-body withdrawal and (2) integrating cardiorespiratory output with these and other motor behaviors.
Whole-body withdrawal is a defensive response of the Lymnaea during which (1) the head-foot is shortened by the simultaneous action of the dorsal longitudinal muscle (DLM) and the columellar muscle (CM) and (2) the CM pulls the shell down to protect the body. Note that the CM and DLM motoneurons are widely distributed across the Lymnaea’s central nervous system. The L/RPeD11 interneurons are responsible for coordinating the simultaneous action of the DLM and CM during whole-body withdrawal.
In addition to its role in coordinating motor movements during whole-body withdrawal, L/RPeD11 interneurons inhibit both muscular and neuronal components of the respiratory behavior. Since whole-body withdrawal and respiration are incompatible in the Lymnaea, activation of the neurons governing muscle movement must coincide with inhibiting firing of the neurons and muscle movements associated with respiration. L/RPeD11 neurons do this by simultaneously triggering a muscle response in their pneumostome (pulmonary opening) and inhibiting the action of interneuron RPeD1, a critical component of the central pattern generator (CPG) that underlies respiratory behavior.
Benjamin, P.R. (2008) Scholarpedia, 3(1):4124. | Full Text.
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