detection of hypoxic conditions in blood by carotid body chemoreceptor signaling
Definition
Target type: biologicalprocess
The process in which information about a lack of oxygen are received and are converted to a molecular signal by chemoreceptors in the carotid bodies. [GOC:mtg_cardio]
The carotid body, a small cluster of chemoreceptors located at the bifurcation of the common carotid artery, plays a crucial role in detecting hypoxic conditions in the blood. This process involves a complex interplay of cellular signaling pathways, ultimately leading to an increase in ventilation and cardiovascular responses to restore oxygen levels.
When oxygen levels in the blood decrease, the carotid body chemoreceptors respond by initiating a cascade of events. These events include:
1. **Decreased oxygen binding to heme:** Oxygen is normally bound to heme molecules within the chemoreceptor cells. When oxygen levels decrease, heme molecules become deoxygenated, triggering a series of cellular signaling events.
2. **Activation of potassium channels:** Deoxygenation of heme leads to the closure of potassium (K+) channels in the chemoreceptor cells. This closure causes an increase in intracellular K+ concentration, depolarizing the cell membrane.
3. **Opening of voltage-gated calcium channels:** Depolarization of the cell membrane triggers the opening of voltage-gated calcium (Ca2+) channels. This influx of Ca2+ into the cell activates various signaling pathways.
4. **Release of neurotransmitters:** The increased intracellular Ca2+ concentration promotes the release of neurotransmitters, such as dopamine and acetylcholine, from the chemoreceptor cells. These neurotransmitters diffuse across the synaptic cleft and bind to receptors on afferent nerve fibers.
5. **Activation of afferent nerve fibers:** Binding of neurotransmitters to receptors on afferent nerve fibers triggers action potentials, which are transmitted to the brainstem.
6. **Integration and response:** The brainstem integrates the signals from the carotid bodies with other sensory information, such as blood pressure and pH. Based on this integration, the brainstem sends signals to various organs and systems, including the respiratory center, the cardiovascular center, and the sympathetic nervous system.
7. **Increased ventilation:** The respiratory center increases the rate and depth of breathing, leading to an increase in oxygen intake.
8. **Cardiovascular responses:** The cardiovascular center increases heart rate and blood pressure, improving oxygen delivery to the tissues.
9. **Sympathetic nervous system activation:** The sympathetic nervous system is activated, contributing to the overall response by further increasing heart rate, blood pressure, and vasoconstriction.
Overall, the carotid body plays a critical role in maintaining oxygen homeostasis by detecting hypoxic conditions in the blood and triggering appropriate physiological responses to restore oxygen levels.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| P2X purinoceptor 2 | A P2X purinoceptor 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UBL9] | Homo sapiens (human) |
Compounds (12)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| pyridoxal phosphate | pyridoxal 5'-phosphate : The monophosphate ester obtained by condensation of phosphoric acid with the primary hydroxy group of pyridoxal. Pyridoxal Phosphate: This is the active form of VITAMIN B 6 serving as a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate (PYRIDOXAMINE). | methylpyridines; monohydroxypyridine; pyridinecarbaldehyde; vitamin B6 phosphate | coenzyme; cofactor; EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor; Escherichia coli metabolite; human metabolite; mouse metabolite; Saccharomyces cerevisiae metabolite |
| pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid | 5'-phosphopyridoxal-6-azobenzene-2,4-disulfonic acid : An arenesulfonic acid that is pyridoxal 5'-phosphate carrying an additional 2,4-disulfophenylazo substituent at position 6. pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid: a novel antagonist that selectively blocks P2 purinoceptor receptors; a useful tool to study co-transmission in tissues when ATP and coexisting neurotransmitters act in concert | arenesulfonic acid; azobenzenes; methylpyridines; monohydroxypyridine; organic phosphate; pyridinecarbaldehyde | purinergic receptor P2X antagonist |
| adenosine diphosphate | Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position. | adenosine 5'-phosphate; purine ribonucleoside 5'-diphosphate | fundamental metabolite; human metabolite |
| diadenosine tetraphosphate | P(1),P(4)-bis(5'-adenosyl) tetraphosphate : A diadenosyl tetraphosphate compound having the two 5'-adenosyl residues attached at the P(1)- and P(4)-positions. | diadenosyl tetraphosphate | Escherichia coli metabolite; mouse metabolite |
| ormetoprim | ormetoprim: proposed chemotherapeutic agent; minor descriptor (75-84); on-line & Index Medicus search PYRIMIDINES (75-84) | dimethoxybenzene | |
| 8-azidoadenosine 5'-triphosphate | |||
| 6-thioinosine-5'-triphosphate | organic molecule | ||
| imd 0354 | N-(3,5-bis(trifluoromethyl)phenyl)-5-chloro-2-hydroxybenzamide: a cardioprotective agent that inhibits IkappaB kinase beta (IKKbeta); structure in first source | benzamides | |
| a-317491 | A-317491: structure in first source | ||
| af 353 | 5-(5-iodo-2-isopropyl-4-methoxyphenoxy)pyrimidine-2,4-diamine: a P2X3 and P2X2/3 receptor antagonist; structure in first source | ||
| a 803467 | A 803467: an Nav1.8 sodium channel blocker; structure in first source | ||
| af-219 | Gefapixant: a P2X3 receptor antagonist |