Related Experiment Video
Updated: Aug 7, 2026
12:13
Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits
Published on: January 25, 2013
Evidence for central chemoreception in the midline raphé
D G Bernard1, A Li, E E Nattie
1Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire 03756-0001, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|January 1, 1996
Summary
Acetazolamide (AZ) injections into the rat brainstem
Area of Science:
- Neuroscience
- Respiratory Physiology
- Chemosensation
Background:
- Central chemosensitivity is crucial for regulating breathing.
- The caudal raphe nucleus is a potential site for central chemoreception.
- Acetazolamide (AZ) induces localized tissue acidosis, serving as a chemosensory probe.
Purpose of the Study:
- To investigate the role of the midline caudal raphe in central ventilatory chemosensitivity.
- To determine if AZ-induced acidosis in the caudal raphe affects respiratory drive.
Main Methods:
- Injections of acetazolamide (AZ), an inactive analogue, or mock cerebrospinal fluid into the caudal raphe of anesthetized, paralyzed, ventilated rats.
- Measurement of integrated phrenic neurogram amplitude to assess respiratory output.
- Anatomical analysis to confirm injection site accuracy.
Main Results:
- AZ injections into the caudal raphe significantly increased phrenic neurogram amplitude in responder rats (8 of 14).
- Responders showed a 43.3% increase in integrated phrenic amplitude 20 minutes post-injection.
- Control injections did not elicit a significant ventilatory response.
Conclusions:
- The midline caudal raphe contains chemosensitive sites that modulate ventilation.
- AZ is effective in probing these chemosensitive sites within the brainstem.
More Related Videos
10:42A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation
Published on: August 18, 2014
06:32Hybridization Chain Reaction RNA Whole-Mount Fluorescence In situ Hybridization of Chemosensory Genes in Mosquito Olfactory Appendages
Published on: November 17, 2023
Related Concept Videos
01:25Olfaction
The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
The olfactory receptors are embedded in the cilia of the...
01:13Functional Brain Systems: Reticular Formation
The reticular formation is a complex network of gray and white matter located within the brainstem extending from the medulla to the midbrain.
Within the reticular formation, there are several distinct nuclei that can be classified into three broad categories. The Raphe nuclei are located along the midline of the brainstem. They are primarily known for their role in synthesizing and releasing serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and circadian rhythms. The...
Within the reticular formation, there are several distinct nuclei that can be classified into three broad categories. The Raphe nuclei are located along the midline of the brainstem. They are primarily known for their role in synthesizing and releasing serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and circadian rhythms. The...
01:20Physiology of Smell and Olfactory Pathway
Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
The olfactory...
01:18Neural Control of Respiration
The neural regulation of respiration is a meticulously coordinated process primarily controlled by the respiratory centers located within the brainstem. These centers, composed of specialized neurons, transmit nerve impulses that control the contraction and relaxation of our respiratory muscles.
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...
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...
01:31Chemical Factors Affecting Respiration Centers
Chemical factors such as changing CO2, O2, and H+ levels in arterial blood play a critical role in influencing respiration depth and rates. These variations are detected by chemoreceptors—specialized sensors located in two primary body areas. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla, while peripheral chemoreceptors are located in the aortic arch and carotid arteries.
CO2 has a potent influence on respiration and is strictly regulated. Under...
CO2 has a potent influence on respiration and is strictly regulated. Under...
01:22Physiology of Respiration II: Neurogenic Control of Respiration
The neurogenic control of respiration coordinates various neural networks and pathways to regulate breathing rate and depth, meeting the body's oxygen and carbon dioxide exchange requirements. This system adapts to physiological and environmental conditions, ensuring optimal breathing patterns.
Central Control
The brainstem is the primary site of central control, hosting respiratory centers:
Central Control
The brainstem is the primary site of central control, hosting respiratory centers: