title: Effects of Hypericum extract on the acetylcholine release: a loose patch clamp approach.
abstract: The St. John's Wort (Hypericum perforatum) extract (Hp) represents one of the most useful natural therapeutic agents in the treatment of moderate and mild depression. The antidepressant effects of Hp are different, by a molecular mechanism point of view, when compared to those of other antidepressant drugs and, we think, a further pharmacological characterization is needed. It is suggested that the neurochemical effects of Hp could be bind either to its activity on the uptake of some mediators in the central nervous system or to the inhibition of some enzymatic activity at the receptor level. The present study carried out with the loose patch clamp (LPC) in the mouse neuromuscular junction, indicates a potentiation of the acetylcholine (ACh) action at the mouse neuromuscular junction. The spontaneous release of ACh was unaffected by Hp indicating that neither presynaptic nor postsynaptic function are modified by Hp. Indeed, both the frequency and the amplitude of the miniature end-plate currents (mepcs) were unmodified by Hp. Furthermore, the mepcs decay time (tau), i.e. the apparent cholinergic channel life time, was significantly increased after Hp treatment. The other parameter affected was the amplitude of the evoked end-plate currents (epcs) which was constantly and in a dose dependent manner increased by Hp. These findings suggest a possible action of Hp on the acetylcholinesterase (AChE) in terms of a reduction of the degradation rate of ACh.
authors.affiliation: Laboratory of Pharmacological Biotechnology, School of Biological Sciences, University of Ancona, Via Ranieri 2, 60131 Ancona, Italy. lambertore@popcsi.unian.it
authors.forename: Lamberto
authors.initials: L
authors.lastname: Re
authors.forename: Cinzia
authors.initials: C
authors.lastname: Corneli
authors.forename: Emanuele
authors.initials: E
authors.lastname: Sturani
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Paolucci
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossini
authors.forename: Olga Sonia
authors.initials: OS
authors.lastname: León
authors.forename: Gregorio
authors.initials: G
authors.lastname: Martínez
authors.forename: Marica
authors.initials: M
authors.lastname: Bordicchia
authors.forename: Quintilio
authors.initials: Q
authors.lastname: Tomassetti
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D020902:Hypericum; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009045:Motor Endplate / Q000187:drug effects* / Q000378:metabolism; D009469:Neuromuscular Junction / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic / Q000187:drug effects*
chemical_list: D010936:Plant Extracts; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D000110:Acetylcholinesterase; D000109:Acetylcholine