Action of cocaine- and amphetamine-regulated transcript (CART) peptide to attenuate cisplatin-induced emesis in Suncus murinus (house musk shrew)

Cocaine- and amphetamine-regulated transcript (CART) peptide is a brain-gut neuropeptide that has been implicated in a range of physiological functions including appetite, which is disturbed during chemotherapy. The aims of the present study were to identify the distribution and expression of CART mRNA and CART peptide, and to examine the potential of CART (55-102) to attenuate cisplatin-induced emesis in Suncus murinus. CART mRNA and peptide were detected throughout the entire brain, including the forebrain, hypothalamus, and brainstem, and also in the gut wall and stomach. In conscious, freely moving animals, intracerebroventricular administration of CART (55-102) did not modulate food and water intake or alter locomotor activity when administered alone. Cisplatin induced emesis and upregulated the expression of CART mRNA in the brainstem. However, CART (55-102) reduced the number of cisplatin-induced retches. Both CART (55-102) and cisplatin increased the number of c-Fos positive cells in the nucleus tractus solitarius, lateral hypothalamus, paraventricular hypothalamus, and bed nucleus of the stria terminalis (BNST), compared to saline-treated animals, whereas cisplatin also induced c-Fos expression in the area postrema (AP), arcuate nucleus, and central nucleus of the amygdala. Pre-treatment with CART (55-102) significantly attenuated the increased c-Fos positive cells in the BNST and AP. These data indicate that CART mRNA and peptide were localized to regions involved in reward/ enforcement, emotion, feeding and emesis. The anti-emetic effect of CART (55-102) against cisplatin-induced emesis may involve both the forebrain limbic system and the brainstem.