ABSTRACT
Histamine was the first mediator implicated in mechanisms of allergy, asthma, and anaphylactic shock because it has been discovered to mimic several features of these diseases. In addition to its well-characterized effects in the acute inflammatory and allergic responses, it was recently demonstrated that histamine regulates several essential events in the immune response. Histamine affects the maturation of system cells and alters their activation, polarization, chemo-taxis, and effect or functions. The case study was General Hospital, Of fa, Kwara State. Histamine also regulates antigen-specific TH1 and TH2 cells, as well as related antibody ISO type responses. Histamine binds to 4 different G protein–coupled receptors that transducer signals to cells through distinct pathways. The expression of these receptors on different cells and cell subsets is regulated, and apparently, the diverse effects of histamine on immune regulation are due to differential expression of 4 histamine receptors and their distinct intracellular signals.
CHAPTER ONE
Introduction
 1.1 Background of the study
Histamine is stored in the granules of mast cells, basophils, platelets. This histamine is released from these cells by the stimuli inducing acute inflammation, anaphylaxis, and histamine releasing factors. Histamine increases the vasodilatation, and also increases the vascular permeability in the immediate transient phase of the acute inflammatory reaction. This act as a chemical mediator in acute inflammation Histamine (2-[4-imodazole]-ethylamine) was discovered as a uterine stimulant in different extracts more than 100 years ago. Its smooth muscle–stimulating and vasode- pressor action was demonstrated in the first experiments by Dale and Laid law.1 In 1927, histamine was isolated from liver and lung tissue, followed by several other tissues, demonstrating that it is a natural constituent of the body, and hence the name histamine was coined after the Greek word for tissue, histos. Now, almost a century after its discovery, histamine research has provided researchers with intensive knowledge about its metabolism, receptors, signal transduction, and physiologic and pathologic effects. How- ever, the complex interrelationship and cross-talk by hista- mine and its receptors remain to be elucidated.
