Effect of some benzodiazepines on peripheral neuromuscular function in the rat in-vitro hemidiaphragm preparation.
The effect of equimolar cumulative concentrations of 11 different benzodiazepines on the indirectly evoked twitch contraction was investigated in the rat in-vitro phrenic nerve-hemidiaphragm preparation. Depending on the pattern of the concentration-response curves two groups of benzodiazepines can be distinguished: (i) a first group with a biphasic action, e.g. potentiation of twitch tension in low concentrations and depression of twitch tension in high concentrations, and (ii) a second group with primary depression of twitch tension with increasing concentrations. All of the tested compounds ultimately caused a 100% depression of twitch tension at concentrations ranging from 0.175 to 0.35 mmol litre-1. Although this peripheral effect of benzodiazepines on neuromuscular function is not the main site of action of these compounds, there are enough arguments to state that it is not a simple toxic effect. There is some evidence from this study that the peripheral component of the benzodiazepine effect on muscle relaxation may involve a multi- rather than one single receptor system.
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001569:Benzodiazepines; D003964:Diaphragm / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D010791:Phrenic Nerve / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D014151:Anti-Anxiety Agents; D001569:Benzodiazepines