The objectives of the proposed research are to understand the primary action of narcotic analgesics and the way in which these alter during the development of tolerance and physical dependence. Intracellular recordings will be made from neurons in the myenteric plexus of the guinea-pig ileum. Acute actions of opiates and opioid peptides will be studied on single membrane ion channels using intracellular voltage clamp (single electrode) combined with extracellular patch clamp recording. The effects of known concentrations of various opiate receptor subtype selective ligands will be applied. The role of intracellular and extracellular calcium ions will be assessed by applying calcium selectively to the inside of the plasma membrane using liposomes. Effects of opiates on transmitter release will be determined by recording synaptic potentials resulting from activity in single fibres. The longer term actions of opiates will be studied by repeating these experiments in neurons removed from guinea-pigs treated with morphine during several days. In addition, adult neurons will be maintained for several days or weeks as a primary explant culture, either with or without morphine. The results are expected to elucidate the primary mechanism of action of narcotic analgesics and opioid peptides on the membrane of excitable cells in both naive and drug dependent animals, and to provide insight into the way in which opiates exert their pharmacological effects and induce tolerance and dependence.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA003160-06
Application #
3207727
Study Section
Pharmacology I Research Subcommittee (DABR)
Project Start
1981-07-01
Project End
1986-12-31
Budget Start
1986-04-01
Budget End
1986-12-31
Support Year
6
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02139
Pessia, M; Jiang, Z G; North, R A et al. (1994) Actions of 5-hydroxytryptamine on ventral tegmental area neurons of the rat in vitro. Brain Res 654:324-30
Busch, A E; Malloy, K; Groh, W J et al. (1994) The novel class III antiarrhythmics NE-10064 and NE-10133 inhibit IsK channels expressed in Xenopus oocytes and IKs in guinea pig cardiac myocytes. Biochem Biophys Res Commun 202:265-70
Kavanaugh, M P; Wang, H; Zhang, Z et al. (1994) Control of cationic amino acid transport and retroviral receptor functions in a membrane protein family. J Biol Chem 269:15445-50
Tanaka, E; North, R A (1994) Opioid actions on rat anterior cingulate cortex neurons in vitro. J Neurosci 14:1106-13
Kavanaugh, M P; Wang, H; Boyd, C A et al. (1994) Cell surface receptor for ecotropic host-range mouse retroviruses: a cationic amino acid transporter. Arch Virol Suppl 9:485-94
Shen, K Z; North, R A (1993) Excitation of rat locus coeruleus neurons by adenosine 5'-triphosphate: ionic mechanism and receptor characterization. J Neurosci 13:894-9
Yakel, J L; Warren, R A; Reppert, S M et al. (1993) Functional expression of adenosine A2b receptor in Xenopus oocytes. Mol Pharmacol 43:277-80
Kavanaugh, M P (1993) Voltage dependence of facilitated arginine flux mediated by the system y+ basic amino acid transporter. Biochemistry 32:5781-5
Sugita, S; Tanaka, E; North, R A (1993) Membrane properties and synaptic potentials of three types of neurone in rat lateral amygdala. J Physiol 460:705-18
Piguet, P; North, R A (1993) Opioid actions at mu and delta receptors in the rat dentate gyrus in vitro. J Pharmacol Exp Ther 266:1139-49

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