Abstract
To examine the role of cholecystokinin1 receptor (CCK 1) in the activation of brainstem and myenteric neurons by CCK, we compared the ability of exogenous CCK-8 to induce Fos-like immunoreactivity (Fos-LI) in these neurons in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, lacking CCK1 receptors, and Long-Evans Tokushima Otsuka (LETO) controls. Five groups (n = 4 rats per group) of OLETF rats, and five LETO control groups, were injected intraperitoneally (IP) with 5, 10, 20, and 40 μg/kg CCK-8 or saline. Forty-micrometer brainstem sections containing the area postrema, nucleus of the solitary tract, and the dorsal motor nucleus of the vagus, and myenteric neurons of the duodenum, jejunum, and ileum underwent a diaminobenzidine reaction enhanced with nickel to reveal Fos-LI. CCK-8 did not increase Fos-LI in any of the tested neurons in the OLETF rats. CCK-8 increased Fos-LI in the brainstem of the LETO rats in a dose dependent manner. In the LETO rats only 40 μg/kg CCK-8 increased Fos-LI in the myenteric plexus of the jejunum. This study demonstrates that CCK-8 activates the brainstem and myenteric neurons through the CCK1 receptor.
Original language | English (US) |
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Pages (from-to) | 1617-1622 |
Number of pages | 6 |
Journal | Peptides |
Volume | 26 |
Issue number | 9 |
DOIs | |
State | Published - Sep 2005 |
Keywords
- Brainstem
- CCK receptor
- Cholecystokinin
- Enteric nervous system
- Fos
- Hindbrain
- LETO
- Myenteric plexus
- OLETF
- Rat
ASJC Scopus subject areas
- Biochemistry
- Physiology
- Endocrinology
- Cellular and Molecular Neuroscience