Protocol for intraventricular injection of retinoids and hypothalamic application of viral vectors in the rat and mouse brain

The brain, specifically the hypothalamus, is a key regulator of the homeostatic balance of numerous biomolecules in the body via its control of the neuroendocrine system. Here, we present a protocol to study body vitamin A balance by injecting synthetic retinoids into the third ventricle of the rat brain. We also describe steps for the intraventricular application of viral vectors to the arcuate nucleus of a mouse brain to knock down vitamin A homeostatic genes. This approach is applicable to the study of vitamin A homeostasis. For complete details on the use and execution of this protocol, please refer to Imoesi et al.1.