Data/hora: 03/06/2024 16:26:08

Provedor de dados: | 48
País: | Chile
Título: | Association of nicotinic acetylcholine receptors with central respiratory control in isolated brainstem-spinal cord preparation of neonatal rats
Autores: | HATORI,EIKI; SAKURABA,SHIGEKI; KASHIWAGI,MASANORI; KURIBAYASHI,JUNYA; TSUJITA,MIKI; HOSOKAWA,YUKI; TAKEDA,JUNZO; KUWANA,SHUN-ICHI.
Data: | 2006-01-01
Ano: | 2006
Palavras-chave: | Brainstem-spinal cord; Neonatal rat; Inspiratory neuron; Preinspiratory neuron; Nicotinic acetylcholine receptor.
Resumo: | Nicotine exposure is a risk factor in several breathing disorders Nicotinic acetylcholine receptors (nAChRs) exist in the ventrolateral medulla, an important site for respiratory control. We examined the effects of nicotinic acetylcholine neurotransmission on central respiratory control by addition of a nAChR agonist or one of various antagonists into superfusion medium in the isolated brainstem-spinal cord from neonatal rats. Ventral C4 neuronal activity was monitored as central respiratory output, and activities of respiratory neurons in the ventrolateral medulla were recorded in whole-cell configuration. RJR-2403 (0.1-10mM), alpha4beta2 nAChR agonist induced dose-dependent increases in respiratory frequency. Non-selective nAChR antagonist mecamylamine (0.1-100mM), alpha4beta2 antagonist dihydro-beta-erythroidine (0.1-100mM), alpha7 antagonist methyllycaconitine (0.1-100mM), and a-bungarotoxin (0.01-10mM) all induced dose-dependent reductions in C4 respiratory rate. We next examined effects of 20mM dihydro-beta-erythroidine and 20mM methyllycaconitine on respiratory neurons. Dihydro-beta-erythroidine induces hyperpolarization and decreases intraburst firing frequency of inspiratory and preinspiratory neurons. In contrast, methyllycaconitine has no effect on the membrane potential of inspiratory neurons, but does decrease their intraburst firing frequency while inducing hyperpolarization and decreasing intraburst firing frequency in preinspiratory neurons. These findings indicate that alpha4beta2 nAChR is involved in both inspiratory and preinspiratory neurons, whereas alpha7 nAChR functions only in preinspiratory neurons to modulate C4 respiratory rate
Tipo: | Journal article
Idioma: | Inglês
Identificador: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000200014
Editor: | Sociedad de Biología de Chile
Formato: | text/html
Fonte: | Biological Research  v.39 n.2 2006