1.1 Introduction
Serotonin is a monoamine neurotransmitter that plays a role in several complex biological functions (David et al., 2016 and Smith et al., 2020). The attribution for the discovery of serotonin is that it occurred serendipitously by Vittorio Erspmarer during his attempt to purify extract from enterochromaffin cells in 1935 (Negri et al., 2016). Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) hydroxylation of the 5 position on the ring, and then decarboxylation to produce serotonin (González-Flores et al., 2011).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Serotonin forms from the hydroxylation (i.e., the addition of -OH group) and decarboxylation of the tryptophan amino acid. The highest concentration of serotonin is in the enterochromaffin cells of the gastrointestinal tract with small amounts in the central nervous system and platelets. Serotonin is primarily found in the enteric nervous system located in the gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, pulmonary neuroendocrine cells and taste receptor cells in the tongue (Schlienger et al., 2003).
Serotonin induces changes in the cell by its action on the serotonergic receptors, which are coupled to different G proteins mediating intracellular changes (Smith et al., 2020). The biological function of serotonin plays several roles in the human body, such as influencing learning, memory, happiness, and reward as well as physiological processes such as regulation of sleep, behavior, and appetite (Kitson, 2007). Serotonin plays a significant role in the pharmacodynamic activities of antidepressants, such as SSRIs and SNRIS. This compound is not only found in mammals but is also present incests, plants, and fungi. Therefore, the consumption of these organisms can affect serotonin levels in humans, occasionally leading to adverse effects (David et al., 2016).
Serotonin, also called 5-hydroxytryptamine, a chemical substance that is derived from the amino acid tryptophan. It occurs in the brain, intestinal tissue, blood platelets, and mast cells and is a constituent of many venoms, including wasp venom and toad venom. Serotonin is a potent vasoconstrictor and functions as a neurotransmitter. It is concentrated in certain areas of the brain, especially the midbrain and the hypothalamus, and changes in its concentration are associated with several mood disorders. Some cases of mental depression are apparently caused by reduced quantities or reduced activity of serotonin in the brain. Several antidepressant drugs achieve their effect by inhibiting the body’s physiological inactivation of serotonin, resulting in the accumulation of that neurotransmitter in the brain (and a consequent elevation of mood). Conversely, excessive serotonin activity in the brain appears to cause such symptoms as migraines and nausea. The hallucinogenic compound LSD may act by inhibiting the action of serotonin (Britannica, 2021).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Biochemistry of Serotonin and its Effect on Brain Cells.
1.3 Statement of Problems
Investigation reveals that the effects of chronic low brain serotonin on, for example, mood may be different both quantitatively and qualitatively from the effects of a few hours of low brain serotonin produced by tryptophan depletion. This is not a limitation of tryptophan supplementation studies.
The brain needs more energy than other cells. Glucose is the only fuel that can be used directly by the brain. Neurons are always in a state of metabolic activity and have constant demand for energy, even during sleep. Because neurons cannot store glucose, they depend on the bloodstream to deliver a constant supply.
The study proposes that the principal function of brain serotonin is to enhance adaptive responses to adverse conditions via two distinct pathways:
- A passive coping pathway which improves stress tolerability; and
- An active coping pathway associated with heightened plasticity, which, with support, can improve an organism’s ability to identify and overcome source(s) of stress by changing outlook and/or behaviour.
1.4 Aim and Objectives of Study
The aim of the study is to assess the Biochemistry of Serotonin and its Effect on Brain Cells. In achieving this aim, the following specific objectives were laid out as follows:
- To investigate the effect of Serotonin on Brain Cells
- To discuss the function of brain serotonin (5-HT) transmission by focusing on two of its major receptor subtypes, the 5-HT1AR and 5-HT2AR
1.5 Significance of Study
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.6 Scope of Study
The study focuses on the Biochemistry of Serotonin and its Effect on Brain Cells.
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).
