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Titolo:
Calcium channels coupled to neurotransmitter release at dually innervated neuromuscular junctions in the newborn rat
Autore:
Santafe, MM; Garcia, N; Lanuza, MA; Uchitel, OD; Tomas, J;
Indirizzi:
Univ Rovira & Virgili, Unitat Histol & Neurobiol, Fac Med & Ciencies Salut, E-43201 Reus, Spain Univ Rovira & Virgili Reus Spain E-43201 cies Salut, E-43201 Reus, Spain Univ Buenos Aires, Fac Ciencias Exactas & Nat, Lab Fisiol & Biol Mol, RA-1428 Buenos Aires, DF, Argentina Univ Buenos Aires Buenos Aires DF Argentina RA-1428 Aires, DF, Argentina
Titolo Testata:
NEUROSCIENCE
fascicolo: 3, volume: 102, anno: 2001,
pagine: 697 - 708
SICI:
0306-4522(2001)102:3<697:CCCTNR>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOTOR-NERVE TERMINALS; OMEGA-AGATOXIN-IVA; SYNAPSE ELIMINATION; TRANSMITTER RELEASE; SKELETAL-MUSCLE; CA2+ CHANNEL; N-TYPE; POLYNEURONAL INNERVATION; ACETYLCHOLINE-RELEASE; POSTNATAL-DEVELOPMENT;
Keywords:
synapse elimination; calcium channels; rat; omega-Conotoxin-GVIA; omega-Agatoxin-IVA; Nitrendipine;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Santafe, MM Univ Rovira & Virgili, Unitat Histol & Neurobiol, Fac Med & Ciencies Salut, Carrer St Llorenc 21, E-43201 Reus, Spain Univ Rovira & Virgili Carrer St Llorenc 21 Reus Spain E-43201
Citazione:
M.M. Santafe et al., "Calcium channels coupled to neurotransmitter release at dually innervated neuromuscular junctions in the newborn rat", NEUROSCIENC, 102(3), 2001, pp. 697-708

Abstract

We studied the effect of several calcium channel blockers (omega -Conotoxin-GVIA, 1 and 3 muM; omega -Agatoxin-IVA, 100 nM; Nitrcndipine. 1 and 10 muM) On evoked transmitter release at singly and dually innervated endplates of the levator auris longus muscle from three- to six-day-old rats. In dually innervated fibers, a second endplate potential may appear after the first one when we increase the stimulation intensity. Thr:lowest and highest endplate potential amplitudes are designated "small endplate potential" and "lage endplate potential" respectively. The percentage of doubly innervated junctions remained, Nevertheless, the percentage of junctions innervated byremains all-nest constant throughout the age range examined three or more terminal axone drops, whereas the singly innervated junctions increase. Therefore, between postnatal days 3 and B, roughly half the neuromuscular junctions may experience the final process of axonal elimination. The synaptic efficacy of the large endplate potential in dual junctions, measured as themean amplitude of the synaptic potential and mean quantal content, was thesame as in the junctions that had become recently mono-innervated in the same postnatal period. In singly innervated fibers, the second plate potential size was strongly reduced by both the P/Q-type voltage-dependent calciumchannel blocker omega -Agatoxin-IVA (79.17 +/- 4.025; P < 0.05) and the N-type voltage-dependent calcium channel blocker <omega>-Conotoxin-GVIA (56.31 +/- 7.80%; P < 0.05), whereas endplate potential amplitude was not significantly changed by the L-type voltage-dependent calcium channel blocker Nitrendipine. In dually innervated fibers, the P/Q-type voltage-dependent calcium channel blocker <omega>-Agatoxin-IVA and L-type voltage-dependent calcium channel blocker Nitrendipine increased the size of the small endplate potential (161.29 +/- 47.87% and 109.32 +/- 11.03%, respectively; P < 0.05 inboth cases) and reduced the large endplate potential (74.42 +/- 15.328 and70.91 +/- 10.04%, respectively; P < 0.05 in both cases). The N-type voltage-dependent calcium channel blocker w-Conotoxin-GVIA significantly increased the small endplate potential in the first few minutes after toxin application (at 10 min: 90.23 +/-. 17.38%; P < 0.05). This increase was not maintained, while the large endplate potential was strongly inhibited (69.25 +/- 7.5%; P < 0.05). In conclusion, in the dually innervated endplates of the newborn rat, presynaptic calcium channel types can have different roles in transmitter release from each of the two inputs, which suggests that nerve terminal voltage-dependent calcium channels are involved in neonatal synaptic maturation. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 22:50:36