Release of Acetylcholine Triggered by the Venom of Glycera Convoluta

Author(s):  
R. Manaranche ◽  
M. Thieffry ◽  
M. Israel
1984 ◽  
Vol 62 (7) ◽  
pp. 857-859 ◽  
Author(s):  
J. S. Richardson ◽  
T. G. Mattio ◽  
E. Giacobini

The electrically stimulated release of [3H]acetylcholine from the parasympathetic nerve terminals of the rat iris in vitro is increased in a dose-dependent manner by scopolamine but is decreased by the tricyclic antidepressants amitriptyline and imipramine. The increased release in the presence of scopolamine seems to be due to the blockade of a presynaptic muscarinic autoreceptor that, in the drug-free state, inhibits the release of acetylcholine. However, at drug concentrations that should have comparable antimuscarinic potency, the antidepressants inhibit the release of acetylcholine. This suggests that the anticholinergic side effects of the antidepressants may be due to the reduced release of acetylcholine from parasympathetic nerve terminals as well as a possible direct postsynaptic muscarinic receptor blocking action. Whatever the mechanism of this action, the antidepressants do not have the same effect as scopolamine at the presynaptic muscarinic autoreceptor in the rat iris.


1991 ◽  
Vol 69 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Bianca B. Ruzicka ◽  
Khem Jhamandas

Previous investigations have shown that the activation of δ-opioid receptors depresses the release of acetylcholine (ACh) in the rat caudate putamen. This finding raised the possibility that the release of ACh is similarly modulated in the globus pallidus, a region containing a distinct population of cholinergic neurons and enriched in enkephalinergic nerve terminals. In the present study the pallidal release of ACh was characterized and the effects of δ-opioid receptor activation on this release were examined. The results show that this release is stimulated by high K+ in a concentration- and Ca2+-dependent manner. D-Pen2,L-Pen5-enkephalin (0.1 – 10 μM), a selective δ-opioid receptor agonist, produced a dose-related inhibition of the 25 mM K+-evoked tritium release. The maximal inhibitory effect, representing a 34% decrease in the K+-induced tritium release, was observed at a concentration of 1 μM. This opioid effect was attenuated by the selective δ-opioid receptor antagonist, ICI 174864 (1 μM). These findings support the role of a δ-opioid receptor in the modulation of ACh release in the rat globus pallidus.Key words: globus pallidus, acetylcholine, enkephalin, release.


2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Raj Kumar

Botulinum toxin is one of the most potent molecule known to mankind. A neurotoxin, with high affinity for cholinergic synapse, is effectively capable of inhibiting the release of acetylcholine. On the other hand, botulinum toxin is therapeutically used for several musculoskeletal disorders. Although most of the therapeutic effect of botulinum toxin is due to temporary skeletal muscle relaxation (mainly due to inhibition of the acetylcholine release), other effects on the nervous system are also investigated. One of the therapeutically investigated areas of the botulinum neurotoxin (BoNT) is the treatment of pain. At present, it is used for several chronic pain diseases, such as myofascial syndrome, headaches, arthritis, and neuropathic pain. Although the effect of botulinum toxin in pain is mainly due to its effect on cholinergic transmission in the somatic and autonomic nervous systems, research suggests that botulinum toxin can also provide benefits related to effects on cholinergic control of cholinergic nociceptive and antinociceptive systems. Furthermore, evidence suggests that botulinum toxin can also affect central nervous system (CNS). In summary, botulinum toxin holds great potential for pain treatments. It may be also useful for the pain treatments where other methods are ineffective with no side effect(s). Further studies will establish the exact analgesic mechanisms, efficacy, and complication of botulinum toxin in chronic pain disorders, and to some extent acute pain disorders.


1997 ◽  
Vol 273 (5) ◽  
pp. G1044-G1050
Author(s):  
Kazuko Shichijo ◽  
Yasuko Sakurai-Yamashita ◽  
Ichiro Sekine ◽  
Kohtaro Taniyama

Neuronal release of endogenous dopamine was identified in mucosa-free preparations (muscle layer including intramural plexus) from guinea pig stomach corpus by measuring tissue dopamine content and dopamine release and by immunohistochemical methods using a dopamine antiserum. Dopamine content in mucosa-free preparations of guinea pig gastric corpus was one-tenth of norepinephrine content. Electrical transmural stimulation of mucosa-free preparations of gastric corpus increased the release of endogenous dopamine in a frequency-dependent (3–20 Hz) manner. The stimulated release of dopamine was prevented by either removal of external Ca2+ or treatment with tetrodotoxin. Dopamine-immunopositive nerve fibers surrounding choline acetyltransferase-immunopositive ganglion cells were seen in the myenteric plexus of whole mount preparations of gastric corpus even after bilateral transection of the splanchnic nerve proximal to the junction with the vagal nerve (section of nerves between the celiac ganglion and stomach). Domperidone and sulpiride potentiated the stimulated release of acetylcholine and reversed the dopamine-induced inhibition of acetylcholine release from mucosa-free preparations. These results indicate that dopamine is physiologically released from neurons and from possible dopaminergic nerve terminals and regulates cholinergic neuronal activity in the corpus of guinea pig stomach.


1985 ◽  
Vol 101 (5) ◽  
pp. 1757-1762 ◽  
Author(s):  
N Morel ◽  
J Marsal ◽  
R Manaranche ◽  
S Lazereg ◽  
J C Mazie ◽  
...  

The presynaptic plasma membrane (PSPM) of cholinergic nerve terminals was purified from Torpedo electric organ using a large-scale procedure. Up to 500 g of frozen electric organ were fractioned in a single run, leading to the isolation of greater than 100 mg of PSPM proteins. The purity of the fraction is similar to that of the synaptosomal plasma membrane obtained after subfractionation of Torpedo synaptosomes as judged by its membrane-bound acetylcholinesterase activity, the number of Glycera convoluta neurotoxin binding sites, and the binding of two monoclonal antibodies directed against PSPM. The specificity of these antibodies for the PSPM is demonstrated by immunofluorescence microscopy.


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