Synaptic connections of cone bipolar cells that express the neurokinin 1 receptor in the rabbit retina.
We have investigated and further characterized, in the rabbit retina, the synaptic connectivity of the ON-type cone bipolar cells that are immunoreactive for an antibody against the neurokinin-1 receptor (NK1R). NK1R-immunoreactive bipolar cell axons terminate in stratum 4 of the inner plexiform layer. The axons of NK1R-positive bipolar cells receive synaptic inputs from amacrine cells through conventional synapses and from putative AII amacrine cells via gap junctions. The major outputs from NK1R-positive bipolar cells make contacts with amacrine cell processes. The most frequent postsynaptic dyads comprise two amacrine cell processes. Double-labeling experiments with antibodies against NK1R and either calretinin or glycine have demonstrated that NK1R-immunoreactive bipolar cells form gap junctions with AII amacrine cells. Thus, NK1R-positive cone bipolar cells, together with calbindin-positive cone bipolar cells, may play an important role in transferring rod signals to the ON-type ganglion cells of the cone pathway in the rabbit retina.
Kim
In-Beom
IB
Department of Anatomy, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seoul, 137-701, South Korea.
Park
Mi Ra
MR
Kang
Tae-Hoon
TH
Kim
Hyun-Ju
HJ
Lee
Eun-Jin
EJ
Ahn
Myung-Douk
MD
Chun
Myung-Hoon
MH
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D017629:Gap Junctions / Q000648:ultrastructure; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D011817:Rabbits; D018040:Receptors, Neurokinin-1 / Q000378:metabolism* / Q000648:ultrastructure; D012160:Retina / Q000378:metabolism / Q000648:ultrastructure*; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology* / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure*
D018040:Receptors, Neurokinin-1