CART (55-102) (rat)

Antinociceptive effects of supraspinal rat cart (55-102) peptide in mice.[Pubmed:12914986]

Brain Res. 2003 Sep 5;983(1-2):233-6.

We investigated the effects of rat cocaine- and amphetamine-regulated transcript CART (55-102) after i.c.v. administration in mouse models of acute and persistent pain. CART was not active in the tail-flick or PPQ tests. It increased the latency to paw licking in the hot-plate test but only at doses that impaired motor function. CART produces antinociception in the formalin test in both phases. Our results suggest that CART is involved in supraspinal pain transmission.

Involvement of the cocaine-amphetamine regulated transcript peptide (CART 55-102) in the modulation of rat immune cell activity.[Pubmed:18580846]

Neuro Endocrinol Lett. 2008 Jun;29(3):359-65.

OBJECTIVE: Cocaine-amphetamine regulated transcript peptides (CART) belong to a neuropeptide family expressed in the central nervous system, especially in the hypothalamus, and also in peripheral tissues. The physiological functions of CART include modulation of pituitary hormone release, regulation of body weight, and the control of feeding behavior and metabolic activity. The reciprocal relationships between CART and immune system function have to be established. Therefore, in the present study we aimed to investigate the influence of CART, administered intracerebroventricularly (icv), on selected immune parameters and pituitary-adrenal axis hormone secretion in the rat. RESEARCH METHODS: In rats submitted to icv infusion of CART or artificial cerebrospinal fluid (aCSF, control) selected immune parameters: splenocyte proliferation (spontaneous and mitogen-stimulated) and peritoneal leukocyte (PTL) activity (spontaneous and phorbol myristate acetate (PMA)-stimulated) were examined 60 and 120 min after treatment. The direct effect of CART on splenocytes in culture in vitro was also examined. Concentration of adrenocorticotrophic hormone (ACTH) and corticosterone was also measured in serum of control and CART infused rats. RESULTS: Splenocytes isolated 60 min after CART infusion exhibited a decreased, albeit non-significant, ability to proliferate spontaneously and were unable to answering to the mitogenic stimulation. This effect was not seen 120 min after CART treatment, which restored splenocyte proliferation decreased by aCSF infusion. CART addition in vitro did not influence proliferation of splenocytes from control rats. Spontaneous activity of peritoneal leukocytes was not modified by CART infusion. PMA-stimulated PTL activity was significantly decreased in aCSF-infused rats 120 min after treatment and CART infusion antagonized this effect. Non-significant increase in serum cortisol after 60 min followed by a significant decrease after 120 min with no change in ACTH concentration was found. CONCLUSION: The immunomodulatory activity of icv-infused CART appears to consist in the creation of a short-lasting immunosuppressive internal milieu, followed by the immunostimulatory one. This first effect was most probably due to the activation of the HPA axis and/or other immunosuppressive peptides, but not through the direct action of CART on immune cells. Thus, CART appears to be short-lasting and indirect modulator of immunity.

Cocaine- and amphetamine-regulated transcript peptide produces anxiety-like behavior in rodents.[Pubmed:12600694]

Eur J Pharmacol. 2003 Mar 7;464(1):49-54.

Cocaine- and amphetamine-regulated transcript (CART) peptide (CART-(55-102)) is involved in the suppression of food intake. We now report that CART-(55-102) is involved in anxiety in rodents. Intracerebroventricularly administered CART-(55-102) as well as intraperitoneal administration of N-methyl-beta-carboline-3-carboxamide (FG-7142), a selective GABA(A)/benzodiazepine receptor inverse agonist, reduced time spent in the open arms in the elevated plus-maze task in mice. CART-(55-102)-induced anxiogenic-like behavior in this task was attenuated by widely prescribed anxiolytics such as diazepam and buspirone. Likewise, CART-(55-102) and FG-7142 significantly reduced social interaction in mice. Both diazepam and buspirone significantly reversed CART-(55-102)-induced anxiogenic-like behavior in social interaction tests. By contrast, another biologically active CART peptide, CART-(62-102), was without effect in the elevated plus-maze task in mice. Moreover, intracerebroventricular administration of CART-(55-102) markedly increased the firing rate of locus coeruleus neurons in single unit recording in anesthetized rats. As CART-(55-102) produced anxiety-like effects in rodents, this peptide may possibly be involved in anxiety and stress-related behavior.

Solution structure of the satiety factor, CART, reveals new functionality of a well-known fold.[Pubmed:11478874]

Biochemistry. 2001 Aug 7;40(31):9082-8.

Cocaine and amphetamine regulated transcript (CART) peptide has been shown to be an anorectic peptide that inhibits both normal and starvation-induced feeding and completely blocks the feeding response induced by neuropeptide Y and regulated by leptin in the hypothalamus. The C-terminal part containing the three disulfide bridges CART(48-89) is the biologically active part of the molecule affecting food intake. The solution structure of the active part of CART has a fold equivalent to other functionally distinct small proteins. CART consists mainly of turns and loops spanned by a compact framework composed by a few small stretches of antiparallel beta-sheet common to cystine knots.

CART, a new anorectic peptide.[Pubmed:9924797]

Int J Biochem Cell Biol. 1998 Dec;30(12):1281-4.

Cocaine and amphetamine regulated transcript peptide (CART), is a recently discovered hypothalamic peptide with a potent appetite suppressing activity. In the rat the CART gene encodes a peptide of either 129 or 116 amino acid residues whereas only the short form exists in humans. The predicted signal sequence is 27 amino acid residues resulting in a prohormone of 102 or 89 residues. The C-terminal end of CART, consisting of 48 amino acid residues and 3 disulphide bonds, is thought to constitute a biologically active part of the molecule. In the central nervous system CART is highly expressed in many hypothalamic nuclei, some of which are involved in regulating feeding behaviour. The CART mRNA is regulated by leptin, and the expressed CART is a potent inhibitor of feeding that even overrides the feeding response induced by neuropeptide Y. The putative CART receptor is therefore a potential therapeutic target for an anti-obesity drug.