Expression of cocaine- and amphetamine-regulated transcript (CART) peptides at climbing fibre-Purkinje cell synapses in the rat vestibular cerebellum

Exercise Modifies the Brain Metabolic Response to Chronic Cocaine Exposure Inhibiting the Stria Terminalis

It is well known that exercise promotes health and wellness, both mentally and physiologically. It has been shown to play a protective role in many diseases, including cardiovascular, neurological, and psychiatric diseases. The present study examined the effects of aerobic exercise on brain glucose metabolic activity in response to chronic cocaine exposure in female Lewis rats. Rats were divided into exercise and sedentary groups. Exercised rats underwent treadmill running for six weeks and were compared to the sedentary rats. Using positron emission tomography (PET) and [18F]-Fluorodeoxyglucose (FDG), metabolic changes in distinct brain regions were observed when comparing cocaine-exposed exercised rats to cocaine-exposed sedentary rats. This included activation of the secondary visual cortex and inhibition in the cerebellum, stria terminalis, thalamus, caudate putamen, and primary somatosensory cortex. The functional network of this brain circuit is involved in sensory processing, fear and stress responses, reward/addiction, and movement. These results show that chronic exercise can alter the brain metabolic response to cocaine treatment in regions associated with emotion, behavior, and the brain reward cascade. This supports previous findings of the potential for aerobic exercise to alter the brain's response to drugs of abuse, providing targets for future investigation. These results can provide insights into the fields of exercise neuroscience, psychiatry, and addiction research.

CART in the brain of vertebrates: circuits, functions and evolution

Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.

Ontogeny of cocaine- and amphetamine-regulated transcript peptide in brain of frog, Microhyla ornata

The cocaine- and amphetamine-regulated transcript (CART) peptide is widely distributed in the brains of adult vertebrates including amphibians. Several physiological roles of CART have been intensely investigated in mammals. Despite these studies, the expression of CART during development of brain has not been studied in amphibians. In the present study, distribution of CART was investigated during development in the post hatched stage 23 to premetamorphic stage 30 of frog Microhyla ornata. CART is expressed as early as in stage 23 in ventral thalamus and rhombencephalon. As development progressed, CART immunoreactivity was observed in the olfactory bulb, telencephalon, rhombencephalon and spinal cord in stage 24. At stage 25, the CART immunoreactivity was observed in the ventromedial thalamic nucleus, posterocentral thalamic nucleus, torus nucleus, central gray and inferior reticular nucleus. In stage 26, CART reactivity was seen in the medial septum, preoptic area, nucleus entopeduncularis, magnocellular nucleus, median eminence, optic tectum, hypophysis and cerebellum. Additionally, CART immunoreactivity was observed in the medial pallium, anterior commissure, nucleus infundibularis dorsalis, ventralis and raphe nucleus at stage 30. The occurrences of CART immunoreactivity at early stage of development suggest that the peptide may have a functional significance during development. The wider appearance of CART in the brain of tadpoles, M. ornata suggests that the peptide may act as a neurohormone during the ontogeny.

Ontogeny of the cocaine- and amphetamine-regulated transcript (CART) neuropeptide system in the brain of zebrafish, Danio rerio

The cocaine- and amphetamine-regulated transcript (CART) peptidergic system is involved in processing diverse neuronal functions in adult animals, including energy metabolism. Although CART is widely distributed in the brain of a range of vertebrates, the ontogeny of this system has not been explored. The CART-immunoreactive system in the zebrafish central nervous system (CNS) was studied across developmental stages until adulthood. The peptide is expressed as early as 24 hours post fertilization and establishes itself in several discrete areas of the brain and spinal cord as development progresses. The trends in CART ontogeny suggest that it may be involved in the establishment of commissural tracts, typically expressing early but subsequently decaying. CART elements are commonly overrepresented in diverse sensory areas like the olfactory, photic, and acoustico-mechanosensory systems, perhaps indicating a role for the peptide in sensory perception. Key neuroendocrine centers, like the preoptic area, hypothalamus, and pituitary, conspicuously show CART innervations, suggesting functions analogous to those demonstrated in other chordates. Uniquely, the epiphysis also appears to employ CART as a neurotransmitter. The entopeduncular nucleus is a major CART-containing group in the adult teleost forebrain that may participate in glucose sensing. This region responds to glucose in the 15-day larvae, suggesting that the energy status sensing CART circuits is active early in development. The pattern of CART expression in zebrafish suggests conserved evolutionary trends among vertebrate species. Developmental expression profiling reveals putative novel functions and establishes zebrafish as a model to investigate CART function in physiology and development.