Actions of dalargin upon single unit activity in the ampullae of Lorenzini of the skate Raja clavata.
In the present study we have shown by single afferent unit recording in electroreceptors of skates (the ampullae of Lorenzini) that the synthetic analogue of leu-enkephalin, dalargin (DAL) at concentrations between 10(-6)-10(-10) M cause a concentration-dependent decrease in the resting discharge frequency as well as a decrease in stimulus evoked responses. The specific opiate antagonist naloxone (NAL, 10(-6) M) antagonizes responses induced by DAL. DAL depresses the excitatory action of L-glutamate (L-GLU). The data obtained speak in favour of the presence of opiate receptors at the synaptic membrane of the ampullae of Lorenzini.
Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg.
G N
GN
Andrianov
G N
GN
Akoev
H A
HA
Braun
I V
IV
Ryzhova
K H
KH
Voigt
N O
NO
Sherman
D000818:Animals; D004594:Electrophysiology; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D009132:Muscles / Q000187:drug effects / Q000294:innervation*; D009270:Naloxone / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects; D012860:Skates, Fish / Q000502:physiology*; D013565:Sympatholytics / Q000494:pharmacology*; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
D013565:Sympatholytics; D009270:Naloxone; D016308:Enkephalin, Leucine-2-Alanine; C040996:enkephalin-Leu, Ala(2)-Arg(6)-