The facilitatory actions of aminopyridines and tetraethylammonium on neuromuscular transmission and muscle contractility in avian muscle

A. L. Harvey, I. G. Marshall

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The actions of 3,4-diaminopyridine, 4-aminopyridine and tetraethylammonium were studied on the chick biventer cervicis muscle preparation. All three compounds produced a greater augmentation of indirectly elicited twitches than of directly elicited twitches. The compounds did not restore transmission in OmMCa2+ solutions but rather produced contractures that were inhibited by acetylcholine receptor antagonists. The compounds restored twitch height in one-tenth normal Ca2+ solutions and induced spontaneous muscle twitching. The compounds reversed dantrolene-induced block of directly elicited twitches. Interactions between tetraethylammonium and 3,4-diaminopyridine were also studied. In indirectly stimulated preparations, the combined effects of the two compounds were more than additive at one concentration level only. In directly stimulated preparations, the effects of 3,4-diaminopyridine were greatly enhanced by tetraethylammonium pretreatment. 3,4-Diaminopyridine pretreatment produced less synergism than tetraethylammonium pretreatment. It is concluded that the actions of the aminopyridines and tetraethylammonium on transmitter release and muscle contractility are essentially similar. These actions are postulated to arise from an inhibitory action on potassium conductance and on ability to release calcium from nerve and muscle membranes. On the basis of the interaction studies, it is suggested that the compounds possess different binding capacities for two different sites on the potassium conducting channel.

Original languageEnglish
Pages (from-to)53-60
Number of pages8
JournalNaunyn-Schmiedeberg's Archives of Pharmacology
Volume299
Issue number1
DOIs
Publication statusPublished - 1 Aug 1977

Fingerprint

Aminopyridines
Tetraethylammonium
Muscles
Dantrolene
4-Aminopyridine
Potassium Channels
Cholinergic Antagonists
Contracture
Cholinergic Receptors
Potassium
Calcium
Membranes
3,4-diaminopyridine

Keywords

  • aminopyridines
  • calcium deficiency
  • potassium conductance
  • tetraethylammonium
  • muscle contraction
  • neuromuscular transmission
  • neurotransmitters
  • synaptic transmission

Cite this

@article{7a43eb63325b4f769b1fda3adc5e9cf4,
title = "The facilitatory actions of aminopyridines and tetraethylammonium on neuromuscular transmission and muscle contractility in avian muscle",
abstract = "The actions of 3,4-diaminopyridine, 4-aminopyridine and tetraethylammonium were studied on the chick biventer cervicis muscle preparation. All three compounds produced a greater augmentation of indirectly elicited twitches than of directly elicited twitches. The compounds did not restore transmission in OmMCa2+ solutions but rather produced contractures that were inhibited by acetylcholine receptor antagonists. The compounds restored twitch height in one-tenth normal Ca2+ solutions and induced spontaneous muscle twitching. The compounds reversed dantrolene-induced block of directly elicited twitches. Interactions between tetraethylammonium and 3,4-diaminopyridine were also studied. In indirectly stimulated preparations, the combined effects of the two compounds were more than additive at one concentration level only. In directly stimulated preparations, the effects of 3,4-diaminopyridine were greatly enhanced by tetraethylammonium pretreatment. 3,4-Diaminopyridine pretreatment produced less synergism than tetraethylammonium pretreatment. It is concluded that the actions of the aminopyridines and tetraethylammonium on transmitter release and muscle contractility are essentially similar. These actions are postulated to arise from an inhibitory action on potassium conductance and on ability to release calcium from nerve and muscle membranes. On the basis of the interaction studies, it is suggested that the compounds possess different binding capacities for two different sites on the potassium conducting channel.",
keywords = "aminopyridines, calcium deficiency, potassium conductance, tetraethylammonium, muscle contraction, neuromuscular transmission, neurotransmitters, synaptic transmission",
author = "Harvey, {A. L.} and Marshall, {I. G.}",
year = "1977",
month = "8",
day = "1",
doi = "10.1007/BF00508637",
language = "English",
volume = "299",
pages = "53--60",
journal = "Naunyn-Schmiedeberg's Archives of Pharmacology",
issn = "0028-1298",
number = "1",

}

TY - JOUR

T1 - The facilitatory actions of aminopyridines and tetraethylammonium on neuromuscular transmission and muscle contractility in avian muscle

AU - Harvey, A. L.

AU - Marshall, I. G.

PY - 1977/8/1

Y1 - 1977/8/1

N2 - The actions of 3,4-diaminopyridine, 4-aminopyridine and tetraethylammonium were studied on the chick biventer cervicis muscle preparation. All three compounds produced a greater augmentation of indirectly elicited twitches than of directly elicited twitches. The compounds did not restore transmission in OmMCa2+ solutions but rather produced contractures that were inhibited by acetylcholine receptor antagonists. The compounds restored twitch height in one-tenth normal Ca2+ solutions and induced spontaneous muscle twitching. The compounds reversed dantrolene-induced block of directly elicited twitches. Interactions between tetraethylammonium and 3,4-diaminopyridine were also studied. In indirectly stimulated preparations, the combined effects of the two compounds were more than additive at one concentration level only. In directly stimulated preparations, the effects of 3,4-diaminopyridine were greatly enhanced by tetraethylammonium pretreatment. 3,4-Diaminopyridine pretreatment produced less synergism than tetraethylammonium pretreatment. It is concluded that the actions of the aminopyridines and tetraethylammonium on transmitter release and muscle contractility are essentially similar. These actions are postulated to arise from an inhibitory action on potassium conductance and on ability to release calcium from nerve and muscle membranes. On the basis of the interaction studies, it is suggested that the compounds possess different binding capacities for two different sites on the potassium conducting channel.

AB - The actions of 3,4-diaminopyridine, 4-aminopyridine and tetraethylammonium were studied on the chick biventer cervicis muscle preparation. All three compounds produced a greater augmentation of indirectly elicited twitches than of directly elicited twitches. The compounds did not restore transmission in OmMCa2+ solutions but rather produced contractures that were inhibited by acetylcholine receptor antagonists. The compounds restored twitch height in one-tenth normal Ca2+ solutions and induced spontaneous muscle twitching. The compounds reversed dantrolene-induced block of directly elicited twitches. Interactions between tetraethylammonium and 3,4-diaminopyridine were also studied. In indirectly stimulated preparations, the combined effects of the two compounds were more than additive at one concentration level only. In directly stimulated preparations, the effects of 3,4-diaminopyridine were greatly enhanced by tetraethylammonium pretreatment. 3,4-Diaminopyridine pretreatment produced less synergism than tetraethylammonium pretreatment. It is concluded that the actions of the aminopyridines and tetraethylammonium on transmitter release and muscle contractility are essentially similar. These actions are postulated to arise from an inhibitory action on potassium conductance and on ability to release calcium from nerve and muscle membranes. On the basis of the interaction studies, it is suggested that the compounds possess different binding capacities for two different sites on the potassium conducting channel.

KW - aminopyridines

KW - calcium deficiency

KW - potassium conductance

KW - tetraethylammonium

KW - muscle contraction

KW - neuromuscular transmission

KW - neurotransmitters

KW - synaptic transmission

UR - http://www.scopus.com/inward/record.url?scp=0017412638&partnerID=8YFLogxK

U2 - 10.1007/BF00508637

DO - 10.1007/BF00508637

M3 - Article

C2 - 20582

AN - SCOPUS:0017412638

VL - 299

SP - 53

EP - 60

JO - Naunyn-Schmiedeberg's Archives of Pharmacology

JF - Naunyn-Schmiedeberg's Archives of Pharmacology

SN - 0028-1298

IS - 1

ER -