Non-sulfated cholecystokinin-8 reduces meal size and prolongs the intermeal interval in male Sprague Dawley rats

Abstract

The current study measured seven feeding responses by non-sulfated cholecystokinin-8 (NS CCK-8) in freely fed adult male Sprague Dawley rats. The peptide (0, 0.5, 1, 3, 5 and 10nmol/kg) was given intraperitoneally (ip) prior to the onset of the dark cycle, and first meal size (MS), second meal size, intermeal interval (IMI) length, satiety ratio (SR = IMI/MS), latency to first meal, duration of first meal, number of meals and 24-hour food intake were measured. We found that NS CCK-8 (0.5 and 1.0nmol/kg) reduced MS, prolonged IMI length and increased SR during the dark cycle. Furthermore, the specific CCK-B receptor antagonist L365, 260 (1 mg/kg, ip) attenuated these responses. These results support a possible role for NS CCK-8 in regulating food intake.

Non-sulfated cholecystokinin-8 increases enteric and hindbrain Fos-like immunoreactivity in male Sprague Dawley rats

“…A positive result may suggest a potential role for these neurons in the feeding responses evoked by NS CCK-8. Our results show that the same dose of NS CCK-8 which reduced food intake in our recent work (0.5 nmol/kg, ip) (Dafalla et al, 2018) also increased Fos-LI in the DVC and the enteric neurons in this study.…”

“…The following morning, the three groups of rats received either S CCK-8 (100 nmol/kg), NS CCK-8 (0.5 nmol/kg) (Bachem, CA) or saline vehicle ip. Our recent study (Dafalla et al, 2018) demonstrated that NS CCK-8 (0.5 nmol/kg) produces significant reduction in food intake relative to saline vehicle.…”

“…Recently (Dafalla et al, 2018), we have shown that NS CCK-8 (0.5 nmol/kg, ip) reduces food intake in adult male Sprague Dawley rats by activating the CCK-BR. The current work demonstrated that the same dose of the peptide increases Fos-LI, a neuronal activation marker, in the DVC of the hindbrain and the enteric neurons of the small intestine.…”

“…Previously, it has been shown that S CCK-8 reduces food intake (Gibbs et al, 1973a) and activates the enteric neurons of the duodenum and the jejunum as well as the DVC (Gulley et al, 2005b;Luckman, 1992;Sayegh and Ritter, 2000). Recently, we have shown that NS CCK-8 also reduces food intake (Dafalla et al, 2018), but, it remains unknown if the peptide activates the DVC and/or the enteric neurons. In the current study, we hypothesized that, similar to S CCK-8, NS CCK-8 increases Fos-LI in the DVC and the enteric neurons of the small intestine.…”

“…CCK (Campos et al, 2012;Williams et al, 2009;Wright et al, 2011;Zheng et al, 2005). In addition, the DVC contains CCK-BR (Noble and Roques, 1999;Noble, 2007), which mediates reduction of food intake by NS CCK-8 (Dafalla et al, 2018), and it can be activated by this peptide (Blevins et al, 2004;Chang and Kapas, 1997;Cox et al, 1995;Della-Fera et al, 1990;Monnikes et al, 1997a;O'Shea and Gundlach, 1993).…”