Distribution of vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide receptors (VPAC1, VPAC2, and PAC1 receptor) in the rat brain.
To examine the distributions of VIP/PACAP receptors (VPAC1, VPAC2, and PAC1 receptors) in the brain and to identify the cell types that express these receptors, we performed immunohistochemistry and double immunofluorescence in the rat brain with specific antibodies. The immunohistochemistry revealed that the receptors had distinctive, complementary, and overlapping distribution patterns. High levels of the VPAC1 receptor were expressed in the cerebral cortex, hippocampal formation, deep cerebellar nuclei, thalamus, hypothalamus, and brainstem. The VPAC2 receptors were concentrated in the cerebral cortex, hippocampal formation, amygdalar regions, cerebellar cortex, deep cerebellar nuclei, hypothalamus, and brainstem. On the other hand, the PAC1 receptors had a more restricted distribution pattern in the brain, and high levels of the PAC1 receptors were confined to the cerebellar cortex, deep cerebellar nuclei, epithalamus, hypothalamus, brainstem, and white matter of many brain regions. Also, many fibers expressing the PAC1 receptors were observed in various areas, i.e., the thalamus, hypothalamus, and brainstem. The double immunofluorescence showed that the VIP/PACAP receptors were confined to the neuroglia as well as the neurons. All three types of the VIP/PACAP receptors were expressed in the astrocytes, and the PAC1 receptors were also expressed in the oligodendrocytes. These findings indicate that VIP and PACAP exert their functions through their receptors in specific locations in different combinations. We hope that this first demonstration of the distributions of the VIP/PACAP receptors provides data useful in the investigation of the mechanisms of the many functions of VIP and PACAP in the brain, which require further elucidation.
Department of Anatomy, Seoul National University College of Medicine, Seoul 110-799, Korea.
Kyeung Min
KM
Joo
Yoon Hee
YH
Chung
Min Kyu
MK
Kim
Ryoung Hee
RH
Nam
Byung Lan
BL
Lee
Kyung Hoon
KH
Lee
Choong Ik
CI
Cha
D000375:Aging / Q000502:physiology; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000145:classification / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014018:Tissue Distribution; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
C495505:Adcyap1r1 protein, rat; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; C495508:Vipr1 protein, rat; C495511:Vipr2 protein, rat; D014660:Vasoactive Intestinal Peptide