title: Neuronal actions of endorphins and enkephalins among brain regions: a comparative microiontophoretic study.
abstract: The brain peptides alpha- and beta-endorphin, leucine- and methionine-enkephalin, as well as the opiate normorphine, have been evaluated by microiontophoresis for their effects on neuronal activity in several regions of the rat brain. In cerebral cortex, brainstem, caudate nucleus, and thalamus, most responsive cells were inhibited by the peptides and by normorphine, while in hippocampus all responsive cells were excited. Both inhibitory and excitatory responses were blocked by the narcotic antagonist naloxone. Occurrence of responsive cells encountered in a particular region was loosely correlated with density of stereospecific opiate binding sites as reported by others. These results are consistent with the hypothesis that the endorphins and enkephalins may represent a new class of central neurotransmitters; among other functions, these peptides may play a role in the regulation of behavior and the expression of psychopharmacological agents such as the opiate alkaloids.
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects*; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D009270:Naloxone / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009842:Oligopeptides / Q000494:pharmacology*; D009928:Organ Specificity; D010455:Peptides / Q000494:pharmacology*; D051381:Rats
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009842:Oligopeptides; D010455:Peptides; D009270:Naloxone
references.citation: Proc Natl Acad Sci U S A. 1976 Sep;73(9):3308-10
references.pmid: 1067621
references.citation: Proc Natl Acad Sci U S A. 1976 Nov;73(11):3942-6
references.pmid: 1069261
references.citation: Science. 1976 Oct 15;194(4262):330-2
references.pmid: 968485
references.citation: Nature. 1976 Jun 3;261(5559):426-7
references.pmid: 934278
references.citation: Brain Res. 1972 Jul 20;42(2):319-35
references.pmid: 4340456
references.citation: Nature. 1973 Oct 26;245(5426):447-50
references.pmid: 4127185
references.citation: Life Sci. 1974 May 16;14(10):1819-34
references.pmid: 4368008
references.citation: Brain Res. 1976 Apr 16;106(1):189-97
references.pmid: 817783
references.citation: Science. 1976 Sep 24;193(4259):1262-3
references.pmid: 986687
references.citation: Proc Natl Acad Sci U S A. 1976 Aug;73(8):2895-8
references.pmid: 8780
references.citation: J Cyclic Nucleotide Res. 1975;1(2):97-106
references.pmid: 4474
references.citation: Br J Pharmacol. 1975 Aug;54(4):529-39
references.pmid: 240474
references.citation: Science. 1975 Aug 15;189(4202):559-61
references.pmid: 167439
references.citation: C R Acad Sci Hebd Seances Acad Sci D. 1976 Feb 23;282(8):783-5
references.pmid: 817843
references.citation: Brain Res. 1976 Aug 13;112(2):407-12
references.pmid: 821584
references.citation: Proc Natl Acad Sci U S A. 1976 Jul;73(7):2515-9
references.pmid: 1065904
references.citation: Proc Natl Acad Sci U S A. 1976 Jun;73(6):2156-9
references.pmid: 1064883
references.citation: Proc Natl Acad Sci U S A. 1976 Jun;73(6):1821-3
references.pmid: 1064855
references.citation: Nature. 1976 Aug 12;262(5569):604-6
references.pmid: 958425
references.citation: Nature. 1976 Aug 12;262(5569):603-4
references.pmid: 958424
references.citation: Nature. 1976 Apr 29;260(5554):793-5
references.pmid: 1264258
references.citation: Nature. 1976 Apr 15;260(5552):625-6
references.pmid: 1264229
references.citation: Mol Pharmacol. 1976 May;12(3):504-13
references.pmid: 934061
references.citation: Neuropharmacology. 1976 May;15(5):273-82
references.pmid: 934439
references.citation: Nature. 1976 Jun 3;261(5559):425-6
references.pmid: 934277
references.citation: Nature. 1976 Jun 3;261(5559):423-5
references.pmid: 934276
references.citation: Life Sci. 1976 Jun 15;18(12):1473-81
references.pmid: 940427
references.citation: J Pharmacol Exp Ther. 1976 Jan;196(1):107-20
references.pmid: 1246005
references.citation: Nature. 1975 Dec 18;258(5536):577-80
references.pmid: 1207728
references.citation: Science. 1969 Dec 5;166(3910):1284-6
references.pmid: 5350323
references.citation: Anesthesiology. 1967 Jan-Feb;28(1):54-64
references.pmid: 6017441
references.citation: Neuroscience. 1976 Aug;1(4):349-51
references.pmid: 11370520
references.citation: Science. 1976 Oct 22;194(4263):440-2
references.pmid: 10625
references.citation: Science. 1976 Nov 5;194(4265):630-2
references.pmid: 185694
references.citation: Endocrinology. 1976 Dec;99(6):1653-4
references.pmid: 187417
references.citation: Brain Res. 1976 Oct 8;115(1):160-4
references.pmid: 987830