GABAergic and glycinergic inhibitory mechanisms in the lamprey respiratory control
Fulvia Bongianni1, Donatella Mutolo, Furio Nardone
1Dipartimento di Scienze Fisiologiche, Universita' degli Studi di Firenze, Viale G.B. Morgagni 63, I-50134 Firenze, Italy.
Abstract:
The specific role of gamma-aminobutyric acid (GABA) and glycine receptors in respiratory rhythm generation and pattern formation was investigated in in vitro brainstem preparations from adult lampreys by analyzing the changes in respiratory activity induced by bath application of specific antagonists, agonists, and uptake blockers. GABAA receptor blockade by bicuculline or picrotoxin increased both the frequency and amplitude of respiratory bursts. Similar effects were observed after glycine receptor blockade by strychnine. Combined bath application of bicuculline and strychnine markedly increased the frequency and amplitude of respiratory activity. These responses were associated, especially at the higher concentrations of the two drugs, with the appearance of tonic activity and irregular, high-frequency bursts followed by transient depression of respiratory activity. GABAA and glycine receptor agonists suppressed respiratory activity. These effects were prevented by bath application of the corresponding specific antagonists. GABAB receptor blockade by 2-hydroxysaclofen reduced the respiratory frequency but increased the peak amplitude of respiratory bursts. Activation of GABAB receptors suppressed respiratory activity. These responses were prevented by 2-hydroxysaclofen. Neither GABAC receptor agonist nor antagonist had any effects on respiration. Depression of both the frequency and amplitude of respiratory bursts was induced by blockades of GABA and glycine uptake using, respectively, nipecotic acid and sarcosine. The results suggest that GABA- and glycine-mediated inhibition is not essential for respiratory rhythm generation in the adult lamprey, although it appears to exert potent influences on respiratory activity and to have a role in maintaining a stable and regular breathing pattern.
More Related Videos
07:16Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
07:51Inhibitory Synapse Formation in a Co-culture Model Incorporating GABAergic Medium Spiny Neurons and HEK293 Cells Stably Expressing GABAA Receptors
Published on: November 14, 2014
Related Concept Videos
Physiology of Respiration II: Neurogenic Control of Respiration
Central Control
The brainstem is the primary site of central control, hosting respiratory centers:
Neural Control of Respiration
Respiratory Centers in the Brainstem
Two primary areas comprise the respiratory center: the medullary respiratory center in the medulla oblongata and the pontine respiratory group in the pons. The...
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
G-Protein Gated Ion Channels
Sensory organs,...
Other Factors Affecting Respiration Centers
However, the ability to hold one's breath voluntarily is not limitless. When the CO2 concentration in the blood reaches a critical level,...
