Serotonin Receptors in Evolution & Developent (Azmitia, 2009, Pt 3.3; XX) скачать в хорошем качестве

Serotonin Receptors in Evolution & Developent (Azmitia, 2009, Pt 3.3; XX)

I. The Evolutionary History of Serotonin Serotonin receptors have very deep evolutionary roots. They likely originated in cyanobacteria billions of years ago. Early receptors functioned to capture light energy. These were primitive rhodopsin GTP-linked receptors. This system predates the evolution of sponges. It is estimated to be 2.5 to 3.5 billion years old. Early cells used these to regulate ion channels. II. Development Mirrors Evolution Embryonic development often reflects evolutionary history. Sea urchin embryos show serotonin binding very early. Receptors appear near the tip of the archenteron. Human 5-HT1A receptor levels peak before birth. These receptors help regulate early brain development. This supports the idea that ontogeny recapitulates phylogeny. Receptors modify ion channels in the developing fetus. III. Diversity In Mammalian Receptors Mammals have developed a wide variety of receptor types. Humans have at least 20 specific receptor transcripts. Serotonin receptors are found in every cell of the body. This diversity helps manage scarcity of tryptophan. Receptors alert cells to chemicals in the environment. This maximizes the efficiency of the serotonin system. Receptors regulate kinases and cAMP levels in neurons. IV. Adaptation & Transport Mechanisms Animals evolved specific proteins to transport tryptophan. Glial cells help concentrate and move tryptophan to neurons. Neurons developed long axons to distribute serotonin. Primates evolved myelinated axons for greater precision. This ensures rapid delivery to targets in the forebrain. Loss of tryptophan promoted a highly branched network. The system is highly adapted for survival and function. V. Additional Resource Support See NourishED RFI's NotebookLM Resource Support Page. https://notebooklm.google.com/noteboo... VI. Source Azmitia, E. C. (2009). Section 3.3 (“Serotonin: Receptors") in Evolution of Serotonin: Sunlight to Suicide. In C. Muller & B. Jacobs (Eds.), Handbook of Behavioral Neurobiology of Serotonin (pp. 3-22). Elsevier. #Serotonin #Evolution #Neuroscience #Biology #BrainDevelopment #Receptors #ScienceEducation #Phylogeny #Neurobiology #CellBiology