negative regulation of blood circulation

Definition

Target type: biologicalprocess

Any process that stops, prevents or reduces the frequency, rate or extent of blood circulation. [GO_REF:0000058, GOC:mr, GOC:TermGenie, PMID:10659969]

Negative regulation of blood circulation is a complex process involving multiple physiological mechanisms that aim to decrease blood flow to specific tissues or organs. This can be achieved through various pathways, including:

1. **Vasodilation:** This involves widening of blood vessels, primarily arteries and arterioles, which reduces resistance to blood flow and decreases blood pressure. This is mediated by the release of vasodilators like nitric oxide (NO), prostaglandins, and adenosine.
2. **Vasoconstriction:** In contrast to vasodilation, vasoconstriction involves narrowing of blood vessels, increasing resistance to blood flow and elevating blood pressure. This is achieved by the release of vasoconstrictors like norepinephrine, angiotensin II, and endothelin.
3. **Cardiac Output Modulation:** The heart's pumping action, known as cardiac output, can be reduced to decrease blood flow. This involves mechanisms like decreased heart rate (bradycardia) or reduced stroke volume (the amount of blood ejected by the heart with each beat).
4. **Blood Viscosity Changes:** Increased blood viscosity, or thickness, can impede blood flow. This can be caused by factors like increased red blood cell count or elevated levels of plasma proteins.
5. **Microvascular Changes:** Alterations in the microvasculature, including the capillaries and venules, can affect blood flow. These changes can involve constriction or dilation of these tiny vessels, as well as increased permeability, leading to fluid leakage and reduced blood flow.

The precise mechanisms and extent of negative regulation of blood circulation vary depending on the specific physiological context. For instance, in response to bleeding, vasoconstriction and increased cardiac output are activated to maintain blood pressure. Conversely, during exercise, vasodilation occurs in skeletal muscles to increase blood flow and deliver oxygen and nutrients.

Furthermore, disruptions in the negative regulation of blood circulation can lead to various pathological conditions, such as hypotension (low blood pressure), circulatory shock, and impaired tissue perfusion.

It's important to note that negative regulation of blood circulation is a tightly controlled process, involving intricate interactions between various physiological systems, including the nervous system, endocrine system, and cardiovascular system.'
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Proteins (1)

Compounds (5)