Abstract
Extracellular discharges of neurons in the paraventricular nucleus (PVN) were recorded from slices of rat hypothalamus in vitro. PVN neurons (n = 14) were identified by the criteria of (i) phasic activity patterns and (ii) antidromic invasion from the neurohypophysial tract. Neurons not displaying either of these features were considered unidentified with respect to physiological function (n = 85). The majority of unidentified neurons responded to bath application of morphine (1 microM), [D-Ala2,Met5]enkephalin (1 microM) or beta-endorphin (0.01-1 microM) with a prompt, reversible, dose-related reduction in spike discharge frequency. Naloxone (1 microM) antagonized the opioid-induced depressions in some, but not all, cases. At the concentrations tested, no tachyphylaxis to the effects of the opioids was observed. The opioid effects on putative neurohypophysial neurons were less pronounced; while 2 were depressed, the remaining 12 displayed no change in frequency or pattern of discharge to micromolar concentrations of morphine, [D-Ala2,Met5]enkephalin, or beta-endorphin. Our results indicate that opioids depress neuronal activity in the rat PVN via an interaction with a specific opiate receptor but that this effect is more pronounced on unidentified neurons than on putative neurohypophysial neurons in the slice.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Atweh S. F., Kuhar M. J. Autoradiographic localization of opiate receptors in rat brain. II. The brain stem. Brain Res. 1977 Jun 24;129(1):1–12. doi: 10.1016/0006-8993(77)90965-9. [DOI] [PubMed] [Google Scholar]
- Baertschi A. J., Dreifuss J. J. Effects of enkephalins and of substance P on the hypothalamo-neuro-hypophysial system of the rat [proceedings]. J Physiol. 1979 Apr;289:56P–57P. [PubMed] [Google Scholar]
- Bisset G. W., Chowdrey H. S., Feldberg W. Release of vasopressin by enkephalin. Br J Pharmacol. 1978 Mar;62(3):370–371. doi: 10.1111/j.1476-5381.1978.tb08472.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bloom F., Battenberg E., Rossier J., Ling N., Guillemin R. Neurons containing beta-endorphin in rat brain exist separately from those containing enkephalin: immunocytochemical studies. Proc Natl Acad Sci U S A. 1978 Mar;75(3):1591–1595. doi: 10.1073/pnas.75.3.1591. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chang K. J., Cuatrecasas P. Multiple opiate receptors. Enkephalins and morphine bind to receptors of different specificity. J Biol Chem. 1979 Apr 25;254(8):2610–2618. [PubMed] [Google Scholar]
- Clarke G., Wood P., Merrick L., Lincoln D. W. Opiate inhibition of peptide release from the neurohumoral terminals of hypothalamic neurones. Nature. 1979 Dec 13;282(5740):746–748. doi: 10.1038/282746a0. [DOI] [PubMed] [Google Scholar]
- Crain S. M., Crain B., Peterson E. R., Simon E. J. Selective depression by opioid peptides of sensory-evoked dorsal-horn network responses in organized spinal cord cultures. Brain Res. 1978 Nov 17;157(1):196–201. doi: 10.1016/0006-8993(78)91014-4. [DOI] [PubMed] [Google Scholar]
- Dingledine R., Iversen L. L., Breuker E. Naloxone as a GABA antagonist: evidence from iontophoretic, receptor binding and convulsant studies. Eur J Pharmacol. 1978 Jan 1;47(1):19–27. doi: 10.1016/0014-2999(78)90369-2. [DOI] [PubMed] [Google Scholar]
- Frederickson R. C. Enkephalin pentapeptides--a review of current evidence for a physiological role in vertebrate neurotransmission. Life Sci. 1977 Jul 1;21(1):23–42. doi: 10.1016/0024-3205(77)90421-0. [DOI] [PubMed] [Google Scholar]
- Fry J. P., Zieglgänsberger W., Herz A. Specific versus non-specific actions of opioids on hippocampal neurones in the rat brain. Brain Res. 1979 Mar 16;163(2):295–305. doi: 10.1016/0006-8993(79)90357-3. [DOI] [PubMed] [Google Scholar]
- Haller E. W., Brimble M. J., Wakerley J. B. Phasic discharge in supraoptic neurones recorded from hypothalamic slices. Exp Brain Res. 1978 Sep 15;33(1):131–134. doi: 10.1007/BF00238799. [DOI] [PubMed] [Google Scholar]
- Hatton G. I., Armstrong W. E., Gregory W. A. Spontaneous and osmotically-stimulated activity in slices of rat hypothalamus. Brain Res Bull. 1978 Sep-Oct;3(5):497–508. doi: 10.1016/0361-9230(78)90079-5. [DOI] [PubMed] [Google Scholar]
- Hill R. G., Pepper C. M., Mitchell J. F. Depression of nociceptive and other neurones in the brain by iontophoretically applied met-enkephalin. Nature. 1976 Aug 12;262(5569):604–606. doi: 10.1038/262604a0. [DOI] [PubMed] [Google Scholar]
- Huidobro F. Antidiuretic effect of morphine in the rat: tolerance and physical dependence. Br J Pharmacol. 1978 Oct;64(2):167–171. doi: 10.1111/j.1476-5381.1978.tb17286.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Inturrisi C. E., Fujimoto J. M. Studies on the antidiuretic action of morphine in the rat. Eur J Pharmacol. 1968 Feb;2(4):301–307. doi: 10.1016/0014-2999(68)90081-2. [DOI] [PubMed] [Google Scholar]
- Iversen L. L., Iversen S. D., Bloom F. E. Opiate receptors influence vasopressin release from nerve terminals in rat neurohypophysis. Nature. 1980 Mar 27;284(5754):350–351. doi: 10.1038/284350a0. [DOI] [PubMed] [Google Scholar]
- Jessell T. M., Iversen L. L. Opiate analgesics inhibit substance P release from rat trigeminal nucleus. Nature. 1977 Aug 11;268(5620):549–551. doi: 10.1038/268549a0. [DOI] [PubMed] [Google Scholar]
- Lord J. A., Waterfield A. A., Hughes J., Kosterlitz H. W. Endogenous opioid peptides: multiple agonists and receptors. Nature. 1977 Jun 9;267(5611):495–499. doi: 10.1038/267495a0. [DOI] [PubMed] [Google Scholar]
- Macdonald R. L., Nelson P. G. Specific-opiate-induced depression of transmitter release from dorsal root ganglion cells in culture. Science. 1978 Mar 31;199(4336):1449–1451. doi: 10.1126/science.204015. [DOI] [PubMed] [Google Scholar]
- Martin W. R. Opioid antagonists. Pharmacol Rev. 1967 Dec;19(4):463–521. [PubMed] [Google Scholar]
- Martinez J. L., Jr, Jensen R. A., Creager R., Veliquette J., Messing R. B., McGaugh J. L., Lynch G. Selective effects of enkephalin on electrical activity of the in vitro hippocampal slice. Behav Neural Biol. 1979 Jun;26(2):128–131. doi: 10.1016/s0163-1047(79)92499-3. [DOI] [PubMed] [Google Scholar]
- Nicoll R. A., Siggins G. R., Ling N., Bloom F. E., Guillemin R. Neuronal actions of endorphins and enkephalins among brain regions: a comparative microiontophoretic study. Proc Natl Acad Sci U S A. 1977 Jun;74(6):2584–2588. doi: 10.1073/pnas.74.6.2584. [DOI] [PMC free article] [PubMed] [Google Scholar]
- North R. A., Katayama Y., Williams J. T. On the mechanism and site of action of enkephalin on single myenteric neurons. Brain Res. 1979 Apr 6;165(1):67–77. doi: 10.1016/0006-8993(79)90045-3. [DOI] [PubMed] [Google Scholar]
- Pepper C. M., Henderson G. Opiates and opioid peptides hyperpolarize locus coeruleus neurons in vitro. Science. 1980 Jul 18;209(4454):394–395. doi: 10.1126/science.7384811. [DOI] [PubMed] [Google Scholar]
- Poulain D. A., Wakerley J. B., Dyball R. E. Electrophysiological differentiation of oxytocin- and vasopressin-secreting neurones. Proc R Soc Lond B Biol Sci. 1977 Apr;196(1125):367–384. doi: 10.1098/rspb.1977.0046. [DOI] [PubMed] [Google Scholar]
- Rossier J., Battenberg E., Pittman Q., Bayon A., Koda L., Miller R., Guillemin R., Bloom F. Hypothalamic enkephalin neurones may regulate the neurohypophysis. Nature. 1979 Feb 22;277(5698):653–655. doi: 10.1038/277653a0. [DOI] [PubMed] [Google Scholar]
- Rossier J., Pittman Q., Bloom F., Guillemin R. Distribution of opioid peptides in the pituitary: a new hypothalamic-pars nervosa enkephalinergic pathway. Fed Proc. 1980 Jun;39(8):2555–2560. [PubMed] [Google Scholar]
- Sar M., Stumpf W. E., Miller R. J., Chang K. J., Cuatrecasas P. Immunohistochemical localization of enkephalin in rat brain and spinal cord. J Comp Neurol. 1978 Nov 1;182(1):17–37. doi: 10.1002/cne.901820103. [DOI] [PubMed] [Google Scholar]
- Satoh M., Zieglgänsberger W., Fries W., Herz A. Opiate agonist-antagonist interaction at cortical neurones of naive and tolerant/dependent rats. Brain Res. 1974 Dec 27;82(2):378–382. doi: 10.1016/0006-8993(74)90624-6. [DOI] [PubMed] [Google Scholar]
- Simantov R., Snyder S. H. Opiate receptor binding in the pituitary gland. Brain Res. 1977 Mar 18;124(1):178–184. doi: 10.1016/0006-8993(77)90877-0. [DOI] [PubMed] [Google Scholar]
- Spencer H. J., Gribkoff V. K., Cotman C. W., Lynch G. S. GDEE antagonism of iontophoretic amino acid excitations in the intact hippocampus and in the hippocampal slice preparation. Brain Res. 1976 Apr 9;105(3):471–481. doi: 10.1016/0006-8993(76)90594-1. [DOI] [PubMed] [Google Scholar]
- Terenius L. Opioid peptides and opiates differ in receptor selectivity. Psychoneuroendocrinology. 1977;2(1):53–58. doi: 10.1016/0306-4530(77)90031-2. [DOI] [PubMed] [Google Scholar]
- Tseng L. F., Loh H. H., Li C. H. betah-endorphin: antidiuretic effects in rats. Int J Pept Protein Res. 1978 Sep;12(3):173–176. doi: 10.1111/j.1399-3011.1978.tb02882.x. [DOI] [PubMed] [Google Scholar]
- Wakerley J. B., Lincoln D. W. The milk-ejection reflex of the rat: a 20- to 40-fold acceleration in the firing of paraventricular neurones during oxytocin release. J Endocrinol. 1973 Jun;57(3):477–493. doi: 10.1677/joe.0.0570477. [DOI] [PubMed] [Google Scholar]
- Williams J. T., North R. A. Effects of endorphins on single myenteric neurons. Brain Res. 1979 Apr 6;165(1):57–65. doi: 10.1016/0006-8993(79)90044-1. [DOI] [PubMed] [Google Scholar]
- Zieglgänsberger W., Bayerl H. The mechanism of inhibition of neuronal activity by opiates in the spinal cord of cat. Brain Res. 1976 Oct 8;115(1):111–128. doi: 10.1016/0006-8993(76)90826-x. [DOI] [PubMed] [Google Scholar]
- Zieglgänsberger W., French E. D., Siggins G. R., Bloom F. E. Opioid peptides may excite hippocampal pyramidal neurons by inhibiting adjacent inhibitory interneurons. Science. 1979 Jul 27;205(4404):415–417. doi: 10.1126/science.451610. [DOI] [PubMed] [Google Scholar]
- Zieglgänsberger W., Tulloch I. F. The effects of methionine- and leucine-enkephalin on spinal neurones of the cat. Brain Res. 1979 May 5;167(1):53–64. doi: 10.1016/0006-8993(79)90262-2. [DOI] [PubMed] [Google Scholar]