Imgenex Corp. develops and commercializes novel reagents for the scientific study of human biology and disease and for the production of new diagnostic assays and potential therapies of such diseases. These novel reagents include antibodies, gene and protein expression systems, and arrays of various cells and tissues for use in studies of functional genomics. Areas of biological interest at IMGENEX include cancer, apoptosis (programmed cell death), molecular signaling pathways, cellular aging, and metabolic and infectious diseases.

Serotonin (5-hydroxytryptamine, 5-HT) mediates many central and peripheral nervous system functions by its interaction with specific neuronal receptors. At least sixteen different 5-HT receptor (5-HTR) subtypes have been identified through molecular cloning and physiological and pharmacological studies. These are classified into seven families, 5-HT1, 5-HT-2, 5-HT3, 5-HT4, 5-HT5, 5-HT6, and 5-HT7. Molecular cloning has identified 5 receptors belonging to 5-HT1 subtype. These are 5-HT1a, 5-HT-1b, 5-HT1c, 5-HT-1d, and 5-HT1eR. The 5-HT2 receptors (5-HT2R) may be considered as a prototype for the serotonin receptors. The 5-HT2AR is implicated in various normal physiological responses, e.g., smooth muscle contraction, headache, mental depression, etc. Serotonin 5-HT2BR is involved in motor control. Serotonin 5-HT3 receptors are distinguished from other 5-HT receptors by their structure and function. . Serotonin 5-HT3 receptors are ligand-gated ion channels that mediate neuronal excitation and exocytotic release of neurotransmitters. Anti-5-HT3R polyclonal antibody shows immunoreactivity in the forebrain), sensory and motor nuclei of brainstem and spinal cord. Serotonin 5-HT4 receptors were first discovered in primary cutures of mouse embryonic colliculi as 5-HT receptor positively coupled to adenylyl cyclase. The 5-HT5 receptors (5-HT5A and 5-HT5B) have been cloned from mouse, rat and human. Localization of 5-HT5AR into a region of chromosome, where mutations lead to abnormal brain development suggests a role of this receptor in brain development. The 5-HT5AR is expressed throughout brain, where as 5-HT5BR expression is restricted to the CA1 region hippocampus. . The sequence of serotonin 5-HT6 receptor is distinct from other 5-HT receptor sequences. The immunohistochemical studies using anti-5-HT6R antibodies suggest that this receptor is widely expressed in rat brain. . Serotonin 5-HT7 receptor family consists of two members, 5-HT7AR and 5-HT7BR. The 5-HT7AR is expressed in kidney, liver, pancreas, spleen, coronary and pulmonary arteries in addition to the brain (hypothalamus, hippocampus, and brainstem). The 5-HT7BR mRNA have mostly been detected in brain tissue, with highest levels in thalamus and hypothalamus and small amounts in the small intestine and aorta.

Our present knowledge of the functions and mechanism of action of each receptor is limited due to the lack of availability of tools that are specific for each individual type of receptors. The need to accurately distinguish between the subtypes of 5-HT receptors is becoming increasingly clear as we realize the role of each individual member in signal transduction, development and differentiation. The antibody/antibodies against specific serotonin receptors are important tools to study the localization of individual serotonin receptors and correlate with functions.