Mihai Nechifor 1 *
1 Department of Pharmacology, Gr. T. Popa University of Medicine and Pharmacy, Iasi, Romania
* Correspondence to: Mihai Nechifor, Department of Pharmacology, Gr. T. Popa University of Medicine and Pharmacy, Iasi, Romania. Phone: +40744508642; E-mail: mihainechif@yahoo.com
Abstract
The imidazoline system is formed by the imidazoline receptors I1, I2 and I3 and the natural competitive agonists that have been identified in the human and animal body: agmatine, harman, harmalan and imidazole-4-acetic acid-ribotide. I1 and I3 receptors are located in the cell membrane. I2 receptors are found as sites on monoamine oxidase A and monoamine oxidase B (MAO-A and MAO-B) and on the mitochondrial membrane. The brain and the cardiovascular system are the structures in the body where most actions of the imidazoline system are known. Imidazoline receptors and their natural agonists are involved in physiological processes but also in the pathogenesis of severe psychiatric and neurological disorders. The most important known implications of this system in neuropsy-chiatric pathology are major depression, addiction and tolerance, neurodegenerative diseases (and primarily in de-mentia), stress, pain and analgesia, seizures, and others. The imidazoline system is involved in normal memory and neuroprotection. This system is also important for some central nervous system vegetative functions. Stimulation of central I1 receptors causes a decrease in blood pressure, increases diuresis and natriuresis, and decreases intraocular pressure. A normal concentration of the main known agonist of imidazoline receptors, agmatine, is important for normal brain function. The plasma concentration of agmatine should be determined in all patients with mood dis-orders, dementia and other neurodegenerative diseases and addictions. Since only a part of agmatine is synthesized in the body and another part is provided by food intake, it is important to use foods rich in this biologically active amine. Today, only moxonidine, rilmenidine (I1 agonists) and clonidine (I1 and alpha2 agonists) are used in clinical practice in the therapy of arterial hypertension, but existing data show that there are possibilities for expanding the clinical use of imidazoline receptor agonists in the future.
