The endomorphin system and its evolving neurophysiological role.
Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) are two endogenous opioid peptides with high affinity and remarkable selectivity for the mu-opioid receptor. The neuroanatomical distribution of endomorphins reflects their potential endogenous role in many major physiological processes, which include perception of pain, responses related to stress, and complex functions such as reward, arousal, and vigilance, as well as autonomic, cognitive, neuroendocrine, and limbic homeostasis. In this review we discuss the biological effects of endomorphin-1 and endomorphin-2 in relation to their distribution in the central and peripheral nervous systems. We describe the relationship between these two mu-opioid receptor-selective peptides and endogenous neurohormones and neurotransmitters. We also evaluate the role of endomorphins from the physiological point of view and report selectively on the most important findings in their pharmacology.
Fichna
Jakub
J
Laboratory of Experimental Neuropsychopharmacology, CNRS FRE 2735, IFRMP 23, Faculty of Medicine & Pharmacy, University of Rouen, 22, Boulevard Gambetta, 76183 Rouen cedex, France.
Janecka
Anna
A
Costentin
Jean
J
Do Rego
Jean-Claude
JC
D000595:Amino Acid Sequence; D000818:Animals; D002490:Central Nervous System / Q000033:anatomy & histology / Q000502:physiology*; D004723:Endorphins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008953:Models, Anatomic; D008954:Models, Biological; D010146:Pain / Q000503:physiopathology; D017933:Peripheral Nervous System / Q000033:anatomy & histology / Q000502:physiology*
D004723:Endorphins