Tetanic stimulation of guinea-pig longitudinal muscle-myenteric plexus preparation causes post-tetanic inhibition of electrically induced single contractions. This effect of tetanic stimulation is believed to result from the mobilization of enkephalins since post-tetanic blockade is inhibited by pretreatment with naloxone. Evidence is presented that prostaglandin E1 or E2 also attenuate post-tetanic blockade and antagonize block of electrically-induced contraction by exogenous enkephalins. The involvement of prostaglandin in the proposed neuronal function of enkephalin is discussed.
EhrenpreisS.GreenbergJ. and Belman: Prostaglandins reverse inhibition of electrically induced contractions of guinea pig ileum by morphine, indomethacin and acetylsalicylic acid. Nature Vol. 245, 280–282, 1973.
2.
EhrenpreisS. and GreenbergJ.: Mechanism of the synaptic effects of morphine, indomethacin and prostaglandins. In Clinical Pharmacology of Psychoactive Drugs edited by E.M. Sellers. Alcoholism and Drug Foundation, Toronto, 1975, pp. 171–182.
3.
EhrenpreisS.GreenbergJ. and ComatyJ.E.: Evidence for a role of prostaglandin in the synaptic effects of opiates and other analgesics on guinea pig ileum. In Tissue Responses to Addictive Drugs edited by D. Ford and D. Clouet. Spectrum Press, New York, 1976, pp. 273–295.
4.
EhrenpreisS.GreenbergJ. and ComatyJ.E.: Block of electrically induced contractions of guinea pig longitudinal muscle by prostaglandin synthetase and receptor inhibitors. Eur. J. Pharmacol. Vol. 39, 331–340, 1976.
5.
KadlecO.HasekK. and SifernaI.: A modulating role of prostag-landins in contractions of the guinea pig ileum. Br. J. Pharmacol. Vol. 51, 565–570, 1974.
6.
HallW.J.O'NeillP. and SheehanJ.D.: The role of prostaglandins in cholinergic neurotransmission in the guinea pig. Eur. J. Pharmacol. Vol. 34, 39–47, 1975.
7.
PuigM.D.,GasconP.,CravisoG.L. and MusacchioJ.M.: Endogenous opiate receptor ligand: Electrically induced release in the guinea pig ileum. Science Vol. 195, 419–420, 1977.
8.
DelangeR.J. and SmithE.L.: Leucine aminopeptidase and other N- termlnal exopeptidases. In The Enzymes edited by F.D. Boyer. Academic Press, New York, 1971, pp. 81–119.
9.
Elkins-KaufmanE. and NeurathH.: Structural requirements for specific inhibitors of carboxypeptidase. J. Biol. Chem. Vol. 178, 645–654, 1949.
10.
MayerD.J.WolfleT.L.AkilH.CarderB. and LiebeskingJ.C.: Analgesia from electrical stimulation in the brainstem of the rat. Science Vol. 174, 1351–1354, 1971.
11.
MelzackR.: Prolonged relief of pain by brief, intense transcutaneous somatic stimulation. PainVol. 1, 357–373, 1975.
12.
AdamsJ.E.: Naloxone reversal of analgesia produced by brain stimu-lation in the human. PainVol. 2, 161–166, 1976.
13.
AkilH.MaddenJ.IV, PatrickR.L. and BarchasJ.O.: Stress- induced increase in endogenous opiate peptides: Concurrent analgesia and its partial reversal by naloxone. In Opiates and Endogenous Opioid Peptides edited by H.W. Kosterlitz. Elsevier/North Holland, New York, 1976, pp. 63–70.
14.
HughesJ.: Isolation of an endogenous compound from the brain with pharmacological properties similar to morphine. Brain Res. Vol. 88, 295–308, 1975.
15.
MeekJ.L.YangH.-Y.T. and CostaE.: Enkephalin catabolism in vitro and in vivo. Neuropharmacol. Vol. 16, 151–154, 1977.
16.
PomeranzB. and ChiuD.: Naloxone blockade of acupuncture analgesia: Endorphin implicated. Life SciencesVol. 19, 1757–1762, 1976.
