کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2847750 1167387 2009 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Role of cholinergic-nicotinic receptors on hypoxic chemoreflex during postnatal development in rats
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی فیزیولوژی
پیش نمایش صفحه اول مقاله
Role of cholinergic-nicotinic receptors on hypoxic chemoreflex during postnatal development in rats
چکیده انگلیسی
We tested the hypothesis that the function of cholinergic-nicotinic receptors on respiration is age dependent. To this end, we used whole body plethysmography to measure breathing frequency (fR), tidal volume (VT) and minute ventilation (V˙E) under normoxia (21% O2) in rats at 1, 4, 7, 12 and 21 postnatal days before and after administration of epibatidine (nicotinic agonist 5 μg/kg, i.p.). In normoxia, epibatidine increased fR and V˙E in a proportionally age-dependent manner (p for age <0.001), without affecting VT. We then focused on P4 and P12 rats, as representative of this developmental pattern, to measure ventilatory response to moderate hypoxia (12% O2, 20 min) after i.p. injection of saline (control), epibatidine (5 μg/kg), or (nicotinic antagonist, 1 mg/kg). At these doses, both drugs selectively target peripheral nicotinic receptors. Epibatidine enhanced the hypoxic ventilatory response while hexamethonium significantly reduced it. These effects were significantly greater in P12 than in P4 rats (p for age <0.001). In P12 rats, in vitro recordings of carotid sinus nerve activity showed that superfusion with nicotine enhanced chemosensory discharge rate in normoxia and hexamethonium reduced the discharge rate in hypoxia. We also identified the nicotinic receptor α7 subunit by immunohistochemistry in carotid bodies from P12 rat. These data show that the role of cholinergic-nicotinic receptor on hypoxic chemoreflex is age dependent and this effect likely implicates carotid body nicotinic receptor activation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Respiratory Physiology & Neurobiology - Volume 169, Issue 3, 31 December 2009, Pages 323-332
نویسندگان
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