Electron-microscopic investigations of vasoactive intestinal peptide (VIP)-like immunoreactive terminal formations in the lateral septum of the pigeon.
Vasoactive intestinal peptide (VIP)-like immunoreactive terminal fields were examined in the lateral septum of the pigeon by means of immunocytochemistry. According to light-microscopic observations, these projections originated from VIP-like immunoreactive cerebrospinal fluid (CSF)-contacting neurons, which are located in the ependymal layer of the lateral septum and form a part of the lateral septal organ. The processes of these cells gave rise to dense terminal-like structures in the lateral septum. Pre-embedding immuno-electron microscopy revealed that VIP-like immunoreactive axon terminals had synaptoid contacts with perikarya of small VIP-immunonegative neurons of the lateral septum, which were characterized by an invaginated nucleus, numerous mitochondria, a well-developed Golgi apparatus, endoplasmic reticulum and a small number of dense-core vesicles (about 100 nm in diameter). VIP-like immunoreactive axons were also seen in contact with immunonegative dendrites in the lateral septum. In both axosomatic and axodendritic connections, VIP-like immunoreactive presynaptic terminals contained large dense-core vesicles, clusters of small vesicles and mitochondria. These findings suggest that VIP-immunoreactive neurons of the lateral septal organ project to small, presumably peptidergic nerve cells of the lateral septum and that the VIP-like neuropeptide serves as a neuromodulator (-transmitter) in this area.
Hirunagi
K
K
Department of Veterinary Anatomy, Faculty of Agriculture, Nagoya University, Japan.
Kiyoshi
K
K
Adachi
A
A
Hasegawa
M
M
Ebihara
S
S
Korf
H W
HW
D000818:Animals; D002552:Cerebral Ventricles / Q000737:chemistry* / Q000648:ultrastructure*; D010856:Columbidae / Q000033:anatomy & histology*; D006056:Golgi Apparatus / Q000648:ultrastructure; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000648:ultrastructure; D009474:Neurons / Q000737:chemistry / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000737:chemistry* / Q000648:ultrastructure*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis* / Q000276:immunology*
D014660:Vasoactive Intestinal Peptide