PSYC 207 Lecture Notes - Lecture 21: Adenylyl Cyclase, Dynorphin, Enkephalin
Document Summary
Made out of long chains of amino acids. Endogenous opioid peptides come from large precursor. Propeptides and then are broken into smaller peptide transmitters. Endogenous opioids are not selective, they show a relative preference for a receptor type. Receptor: preferentially activated by enkephalins and endorphins. All opioids are coupled with a g proteins that inhibit adenylyl cyclase. G protein modulation of k+ channels causing cell to be hyperpolarized. G protein modulation of ca2+ channels decreases the release of neurotransmission. Nociceptors: networks of free nerve endings that are sensitive to pressure, temperature, electrical impulses. Nociception: communication of pain sensations in the nervous system. A fibers: carry pain signals, large diameter, myelinated, fast. C fibers: carry pain signals, smaller in diameter, unmyelinated, slower. Early pain: activates primary somatosensory cortex contralaterally. With in spinal cord through small inhibitory interneurons. By two descending pathways originating in the periaqueductal gray. Pag: rich in endogenous opioids peptides and high concentrations of u and k receptors.
