Immunohistochemical distribution of substance P, serotonin, and methionine enkephalin in sexually dimorphic nuclei of the rat lumbar spinal cord

1986 ◽  
Vol 248 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Paul E. Micevych ◽  
Arthur Coquelin ◽  
Arthur P. Arnold
Endocrinology ◽  
2010 ◽  
Vol 151 (1) ◽  
pp. 417-421 ◽  
Author(s):  
Hirotaka Sakamoto ◽  
Tatsuo Arii ◽  
Mitsuhiro Kawata

Abstract The spinal nucleus of bulbocavernosus (SNB) is a sexually dimorphic motor nucleus located in the anterior horn of the fifth and sixth lumbar segments of the spinal cord that plays a significant role in male sexual function. We recently found that a sexually dimorphic expression of gastrin-releasing peptide (GRP) in the lumbar spinal cord regulates male copulatory reflexes. Although it is reported that these systems are both profoundly regulated by circulating androgen levels in male rats, no direct evidence has been reported regarding GRP synaptic inputs onto SNB motoneurons. The aim of the current study was to determine the axodendritic synaptic inputs of spinal GRP neurons to SNB motoneurons. Immunoelectron microscopy, combined with a retrograde tracing technique using high-voltage electron microscopy (HVEM), provided a three-dimensional visualization of synaptic contacts from the GRP system in the lumbar spinal cord onto SNB motoneurons. HVEM analysis clearly demonstrated that GRP-immunoreactive axon terminals directly contact dendrites that extend into the dorsal gray commissure from the SNB. These HVEM findings provide an ultrastructural basis for understanding how the spinal GRP system regulates male sexual behavior.


1995 ◽  
Vol 674 (2) ◽  
pp. 336-340 ◽  
Author(s):  
Yu-Qiang Ding ◽  
Masahiko Takada ◽  
Ryuichi Shigemoto ◽  
Noboru Mizuno

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