کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2846676 1571301 2016 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Activity-dependent plasticity in the isolated embryonic avian brainstem following manipulations of rhythmic spontaneous neural activity
ترجمه فارسی عنوان
پلاستیسیتهای وابسته به فعالیت در مغز استخوان انسدادی جنینی پس از دستکاری فعالیتهای عصبی خودبخود ریتمیک
کلمات کلیدی
قرار گرفتن در معرض نیکوتین رشد، مغز شاخی، پرندگان پلاستیک وابسته به فعالیت در فضای باز
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی فیزیولوژی
چکیده انگلیسی


• We studied day 5-5.5 chick embryos when bioelectric brainstem rhythms are first present.
• We studied early nicotine exposure and its effect on rhythmic spontaneous neural activity.
• Spontaneous neural activity adapts to alterations in excitatory drive.
• Changes in GABAergic/glycinergic neurotransmission are responsible for early compensatory neuroplasticity.

When rhythmic spontaneous neural activity (rSNA) first appears in the embryonic chick brainstem and cranial nerve motor axons it is principally driven by nicotinic neurotransmission (NT). At this early age, the nicotinic acetylcholine receptor (nAChR) agonist nicotine is known to critically disrupt rSNA at low concentrations (0.1–0.5 μM), which are levels that mimic the blood plasma levels of a fetus following maternal cigarette smoking. Thus, we quantified the effect of persistent exposure to exogenous nicotine on rSNA using an in vitro developmental model. We found that rSNA was eliminated by continuous bath application of exogenous nicotine, but rSNA recovered activity within 6–12 h despite the persistent activation and desensitization of nAChRs. During the recovery period rSNA was critically driven by chloride-mediated membrane depolarization instead of nicotinic NT. To test whether this observed compensation was unique to the antagonism of nicotinic NT or whether the loss of spiking behavior also played a role, we eliminated rSNA by lowering overall excitatory drive with a low [K+]o superfusate. In this context, rSNA again recovered, although the recovery time was much quicker, and exhibited a lower frequency, higher duration, and an increase in the number of bursts per episode when compared to control embryos. Importantly, we show that the main compensatory response to lower overall excitatory drive, similar to nicotinergic block, is a result of potentiated chloride mediated membrane depolarization. These results support increasing evidence that early neural circuits sense spiking behavior to maintain primordial bioelectric rhythms. Understanding the nature of developmental plasticity in the nervous system, especially versions that preserve rhythmic behaviors following clinically meaningful environmental stimuli, both normal and pathological, will require similar studies to determine the consequences of feedback compensation at more mature chronological ages.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Respiratory Physiology & Neurobiology - Volume 229, 15 July 2016, Pages 24–33
نویسندگان
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