Receptors basic properties

Agonism and Inverse Agonism Are the Basic Properties of Ligands Alone on the Receptor... 

In addition to this culturally and individually conditioned relativity, the fact that each person is human and therefore born with certain basic properties in his nervous system, sensory receptors, and perhaps in the nature of the awareness that enters into or comes from the operation of his nervous system, equips him with built-in biases for seeing the universe in certain kinds of ways and not other ways. This applies not only to the external universe perceived through his senses or with instrumental aids, but to his observations of his own internal experiences. 

HiSTAMiNE RECEPTOR AGONiSTS act at one or more of the three receptor types that have been defined - Hj, H2 and Hj. Histamine itself can act at any of these sites, which have a variety of contrasting properties. The basic properties of these will be described, then followed by a description of the pharmacology of histamine. Antagonists at these receptors are described under separate headings see HISTAMINE Hi-RECEPTOR ANTAGONISTS HISTAMINE Hj-RECEPTOR... 

Before delving into the particulars of individual signaling pathways, we discuss the basic properties of cell-surface receptors, as well as methods for identifying and studying them, in the remainder of this section Important general features of Intracellular signal transduction are presented in Section 13.2. 

A basic premise in receptor pharmacology is that all drugs have affinity for receptors (the chemical property that unites the dmg with the receptor), and some drugs have efficacy, the chemical property that causes the receptor to change its behavior toward its host cell. Drugs that have efficacy can produce concentration-dependent responses in physiological systems, characterized by a concentration-response curve (also often referred to as a dose-response cuive). 

The lateral diverticulum cells in semi-terrestrial species such as toads can still detect a wide range of amino acids, comparable to the properties of fish neuroepithelium. Both water-soluble and volatile odourants are discriminated by the olfactory neurones of the Clawed toad (Xenopus) (Iida and Kashiwayanagi, 1999). When single olfactory neurones were tested with acidic, neutral and basic amino acids, over 50% of the receptors gave some excitatory response. 

The basic biology of chemokines and their receptors is well covered in Chapters 2 and 3 of this book, and we will focus hereafter upon the roles of individual chemokines and receptors in atherosclerosis. The largest amount of data on the roles of chemokines in cardiovascular disease (C VD) has been obtained from in vitro studies and murine models, which will be discussed in detail. In man, genetic polymorphisms in chemokine and chemokine-receptor genes have pointed to an important role for specific chemokines in various atherosclerotic diseases including coronary artery disease and carotid artery occlusive disease. For properties see Table 1. 

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