Acetyl-L-carnitine is known to improve many aspects of the neural activity even if its exact role in neurotransmission is
still unknown. This study investigates the effects of acetyl-L-carnitine in T segmental sensory neurons of the leech Hirudo
medicinalis. These neurons are involved in some forms of neural plasticity associated with learning processes.
Their physiological firing is accompanied by a large afterhyperpolarization that is mainly due to the Na+/K+ ATPase
activity and partially to a Ca2+-dependent K+ current. A clear-cut hyperpolarization and a significant increase of the
afterhyperpolarization have been recorded in T neurons of leeches injected with 2 mM acetyl-L-carnitine some days
before. Acute treatments of 50 mM acetyl-L-carnitine induced similar effects in T cells of naive animals.
Moreover, in these cells, widely arborized, the afterhyperpolarization seems to play an important role in determining
the action potential transmission at neuritic bifurcations.
A computational model of a T cell has been previously developed considering detailed data for geometry and the
modulation of the pump current. Herein, we showed that to a larger afterhyperpolarization, due to the
acetyl-L-carnitine-induced effects, corresponds a decrement in the number of action potentials
reaching synaptic terminals.
Lombardo P, Scuri R, Cataldo E, Calvani M, Nicolai R, Mosconi L, Brunelli M (2004) Acetyl-L-carnitine induces a sustained potentiation of the afterhyperpolarization. Neuroscience 128:293-303 [PubMed]