title: Physiological characterization of human muscle acetylcholine receptors from ALS patients.
abstract: Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of motor neurons leading to muscle paralysis. Research in transgenic mice suggests that the muscle actively contributes to the disease onset, but such studies are difficult to pursue in humans and in vitro models would represent a good starting point. In this work we show that tiny amounts of muscle from ALS or from control denervated muscle, obtained by needle biopsy, are amenable to functional characterization by two different technical approaches: "microtransplantation" of muscle membranes into Xenopus oocytes and culture of myogenic satellite cells. Acetylcholine (ACh)-evoked currents and unitary events were characterized in oocytes and multinucleated myotubes. We found that ALS acetylcholine receptors (AChRs) retain their native physiological characteristics, being activated by ACh and nicotine and blocked by α-bungarotoxin (α-BuTX), d-tubocurarine (dTC), and galantamine. The reversal potential of ACh-evoked currents and the unitary channel behavior were also typical of normal muscle AChRs. Interestingly, in oocytes injected with muscle membranes derived from ALS patients, the AChRs showed a significant decrease in ACh affinity, compared with denervated controls. Finally, riluzole, the only drug currently used against ALS, reduced, in a dose-dependent manner, the ACh-evoked currents, indicating that its action remains to be fully characterized. The two methods described here will be important tools for elucidating the role of muscle in ALS pathogenesis and for developing drugs to counter the effects of this disease.
authors: Dipartimento di Fisiologia e Farmacologia, Istituto Pasteur-Fondazione Cenci Bolognetti, Università Sapienza, 00185 Rome, Italy. eleonora.palma@uniroma1.it
authors: Eleonora
authors: E
authors: Palma
authors: Maurizio
authors: M
authors: Inghilleri
authors: Luca
authors: L
authors: Conti
authors: Cristina
authors: C
authors: Deflorio
authors: Vittorio
authors: V
authors: Frasca
authors: Alessia
authors: A
authors: Manteca
authors: Floriana
authors: F
authors: Pichiorri
authors: Cristina
authors: C
authors: Roseti
authors: Gregorio
authors: G
authors: Torchia
authors: Cristina
authors: C
authors: Limatola
authors: Francesca
authors: F
authors: Grassi
authors: Ricardo
authors: R
authors: Miledi
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000690:Amyotrophic Lateral Sclerosis / Q000188:drug therapy / Q000378:metabolism*; D000818:Animals; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000473:pathology; D009132:Muscles / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000502:physiology; D019782:Riluzole / Q000494:pharmacology / Q000627:therapeutic use; D014981:Xenopus
chemical_list: D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D019782:Riluzole; D000109:Acetylcholine