ABSTRACT
The effects of naloxone on rhythmic activity of the identified helix neurons possessing pacemaker properties were investigated. It has been found that the cellular responses on applications of naloxone (10-100 iM) depended on the type of a neuron. The effect of naloxone is likely to be mediated by the specific ionotropic opiate receptors which are under the control of endogenous opioids.
Subject(s)
Ganglia, Invertebrate/drug effects , Helix, Snails/drug effects , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Neurons/drug effects , Animals , Ganglia, Invertebrate/cytology , Ganglia, Invertebrate/physiology , Membrane Potentials/drug effectsABSTRACT
The effect of the plant triterpene saponins on Helix pomatia neurons is investigated. It was found that monodesmosidic saponins being perfused to the extracellular solution at concentrations 2[symbol: see text] 10(-3)-10(-4) M induced persistent hyperpolarization of the neurons. By using the patch-clamp technique it was obtained that these substances increased the amplitude of the outward potassium current. At lower concentrations (10(-5)-10(-7) M) saponins either led to the transient reversible oppression of the impulse activity, or didn't change the background activity. The influence of saponins is unspecific and develops during 1-2 min. It was supposed that the effect of triterpene saponins at high concentrations was related with the appearance of nonselective holes in neuron membrane.
