المفاهيم الأساسية
Bicuculline injections at rostral parafacial locations (+0.6 mm and +0.8 mm from the facial nucleus) elicit the most robust and enduring changes in respiratory parameters, indicating this region as the core for active expiration generation.
الملخص
The study employed focal injections of bicuculline, a GABA-A receptor antagonist, at various rostrocaudal locations of the lateral parafacial region (-0.2 mm to +0.8 mm from the facial nucleus) to investigate the impact of GABAergic disinhibition on respiration.
Key highlights:
- Bicuculline injections consistently elicited abdominal (ABD) muscle recruitment across all locations, but the response strength varied along the rostrocaudal axis.
- The most robust and enduring changes in tidal volume, minute ventilation, and combined respiratory responses occurred at the two most rostral locations (+0.6 mm and +0.8 mm).
- ABD activation lasted longer and the onset was fastest at the +0.6 mm location.
- Multivariate analysis of the respiratory cycle further differentiated the responses, with the +0.8 mm location showing the strongest deformations during late-expiration and post-inspiration, while the +0.6 mm location produced more pronounced changes during inspiration.
- These findings indicate the rostral parafacial region as the core for active expiration generation and provide a foundation for future investigations into the modulation and potential therapeutic targeting of this respiratory control mechanism.
الإحصائيات
The injection of bicuculline along the rostrocaudal axis of the ventral medulla induced a drop in respiratory frequency in all the injection sites tested, with the most caudal groups (-0.2 mm and +0.1 mm) experiencing a faster and more drastic reduction.
The increase in tidal volume (VT) peaked at 4 min post-injection, with the +0.6 mm location showing a higher peak VT compared to the two most caudal groups.
Minute ventilation (VE) decreased in the most caudal group (-0.2 mm), whereas it increased in the most rostral locations (+0.4 mm, +0.6 mm, +0.8 mm).
Oxygen consumption (VO2) remained similar to baseline at the 3 most caudal locations but dropped from baseline at the most rostral sites (+0.6 mm and +0.8 mm), leading to an increase in the VE/VO2 ratio.
اقتباسات
"Bicuculline injections at +0.6 mm from VIIc initiated the fastest response, suggesting proximity to the cells responsible for ABD recruitment following bicuculline injection."
"The reduction in VO2 paired with the increases in VE observed at the most rostral injection sites, resulted in hyperventilation, an effect which was not observed in the two most caudal groups."