Neurochemistry is a burgeoning academic field that donates to our understanding of molecular, cellular and medical neurobiology. Neurochemicals contain oxytocin, serotonin, dopamine and other neurotransmitters and neurotransmitter-regulating substances. Neurochemical studies explain scientific tools for neurochemicals in the nervous system. These comprise identification and characterization of neurotransmitters and neuromodulators helpful for neurotransmission in neuronal and glial cells networks in the brain. Neurochemical techniques are valuable to examine the physiological mechanism of normal brain function such as synaptic transmission, plasticity and neurogenesis. Conversely, these techniques are available to find pathogenesis of the brain. The book presents cutting-edge research and reviews in these different disciplines written by renowned experts in their particular fields. Neurodegeneration and neuronal diseases are featured prominently and are a recurring theme throughout most chapters. Many physiological processes like muscle contraction, hormone secretion and intracellular signalling processes are triggered by calcium as intracellular signalling molecule. TRP channels are integrated in many cellular signal transduction pathways and a variety of physiological processes as discussed in this book. TRP channels have been identified and characterized by common biochemical, immunochemical and physiological methods. MicroRNAs (miRNAs) are small regulatory RNAs that have an important role in elementary biological processes, such as cell proliferation, cell differentiation and cell death. Correlation between miRNAs and cancer and abnormal expression of miRNAs has been shown in a variety of tumor tissues including pituitary adenomas. By regulating their target genes expression, miRNAs can play either oncogenic or tumor suppressor functions. Herein, we investigated miRNA expression profile of pituitary oncocytomas and evaluated the role of differentially expressed miRNAs by complex bioinformatical approaches. Further, the book focuses on blood brain barrier. The blood brain barrier (BBB) is a selectively permeable cellular boundary between the brain and the peripheral circulation. The BBB is responsible for maintaining the appropriate ionic composition of the interstitial fluid of the brain that is required for optimum functioning of the neurons. To achieve this, the BBB functions as a transport barrier by facilitating the uptake of the required nutrients, while preventing the uptake of, or actively effluxing certain other molecules or toxic by-products of metabolism. The book also sheds light on blood vessels as regulators of neural stem cell properties and NMDA receptor dependent long-term potentiation in chronic pain. The book concludes that gut-to-brain communication from the vagus nerve and from feeding-relevant endocrine systems; including ghrelin, insulin, leptin, and glucagon-like peptide-1 (GLP-1), promote hippocampal-dependent spatial and declarative memory via neurotrophic and neurogenic mechanisms. The collective literature reviewed herein supports a model in which various stages of feeding behavior and hippocampal-dependent memory function are closely linked. This book will serve as most valuable guide for neurochemists and other scientists as well.