Pathway 13-8-2 Regulation of Pulpal Blood Flow （dilation vs constriction 的因子）

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Questions and Answers

What primary mechanism contributes to the increase in pulpal blood flow following electrical tooth stimulation?

Release of substance P

Increase in systemic blood pressure

Sympathetic nervous system activation

Release of sensory neuropeptides mainly CGRP (correct)

Which receptor type is responsible for the vasoconstriction observed in the dental pulp?

a-adrenergic receptors (correct)

Dopamine receptors

Histamine receptors

β-adrenergic receptors

What is the role of neuropeptide Y (NPY) and NE (Nor-epinephrine) in the dental pulp?

It has no effect on pulpal vascular tone.

It contributes to vasoconstriction in the pulp. (correct)

It promotes vasodilatation during resting conditions.

It enhances systemic blood pressure.

Which of the following statements is true regarding the modulation of pulpal blood flow?

Vasodilatation in adjacent tissues can reduce pulpal blood flow. Signup and view all the answers

What effect does acetylcholine (ACh) have on pulpal blood flow?

It induces vasodilatation. Signup and view all the answers

Which of the following best describes the influence of systemic blood pressure on pulpal blood flow?

Pulpal blood flow follows changes in systemic blood pressure passively. Signup and view all the answers

Which substance released from sensory nerve fibers is primarily responsible for vasodilatation in the dental pulp?

Calcitonin gene-related peptide (CGRP) Signup and view all the answers

Which factor contributes to the 'stealing' of dental perfusion pressure in the context of adjacent inflammatory processes?

Vasodilatation in the surrounding tissues. Signup and view all the answers

What is the primary substance released from sensory nerve fibers that induces vasodilatation?

CGRP Signup and view all the answers

Which of the following is a vasodilatory substance found in CGRP negative sensory afferent nerve fibers in the pulp?

Glutamate GLU Signup and view all the answers

What role does ACh play in the regulation of blood flow?

It causes vasodilation and increases blood flow. Signup and view all the answers

⭐️What is one of the factors that ACh-induced vasodilation depends on?

Nitric oxide (NO) production. Signup and view all the answers

Which of the following best describes the interaction between ACh and nitric oxide in blood flow regulation?

ACh stimulates NO production, enhancing vasodilation. Signup and view all the answers

In addition to ACh, which other neurotransmitter or factor is known to influence vasodilation in tissues?

Nitric oxide. Signup and view all the answers

Which of the following statements correctly describes the function of vasoactive intestinal polypeptide (VIP) in the dental pulp?

VIP plays a role in increasing pulpal blood flow through vasodilatation. Signup and view all the answers

⭐️What neuropeptide ⭐️coexists⭐️ with acetylcholine (ACh) in postganglionic neurons?

Vasoactive intestinal polypeptide (VIP) Signup and view all the answers

In which species has vasoactive intestinal polypeptide (VIP) been demonstrated to cause vasodilatation and increase in pulpal blood flow?

Cats Signup and view all the answers

Which of the following best describes the role of vasoactive intestinal polypeptide (VIP) in relation to ACh?

VIP enhances the effects of ACh in postganglionic neurons. Signup and view all the answers

What is the probable effect of VIP in the dental pulp?

Vasodilatation and increased pulpal blood flow Signup and view all the answers

Study Notes

Pulpal Blood Flow Regulation

Pulpal blood flow (PBF) is maintained in a state of partial constriction due to neuronal, paracrine, and endocrine mechanisms.
PBF is passively influenced by systemic blood pressure changes, meaning there is no autoregulation.
Vasodilation in surrounding tissues, such as gingiva and periodontal structures, can cause a drop in PBF by "stealing" perfusion pressure from the dental pulp.
Sympathetic nervous system has little to no vasoconstrictor tone at rest in the pulp.
Sensory neuropeptide release from sensory nerves provides a neuronal vasodilatory tone.
α-adrenergic receptors are found within the pulp, stimulating them causes vasoconstriction and reduced PBF, partially reversed by α-receptor blockade.
Neuropeptide Y (NPY), colocalized with norepinephrine (NE) in the pulpal sympathetic nerve fibers, also contributes to vasoconstriction.
Electrical tooth stimulation causes an increase in PBF due to sensory neuropeptide release and subsequent vasodilation.
Calcitonin gene-related peptide (CGRP) is the primary mediator of vasodilatation released from sensory nerve fibers.
Glutamate, present in CGRP-negative sensory afferent nerve fibers, exhibits vasodilatory effects.
Sympathetic modulation of sensory neuropeptide release occurs in the dental pulp through presynaptic α-receptors on sensory nerve terminals, attenuating vasodilator release.
Muscarinic receptors are present in the pulp, with acetylcholine (ACh) causing vasodilatation and increased blood flow.
ACh-induced vasodilation is partially reliant on nitric oxide (NO) production.
Vasoactive intestinal polypeptide (VIP), colocalized with ACh in postganglionic neurons, is found in the dental pulp and causes vasodilatation and increased PBF.
Research on parasympathetic nerve-evoked vasodilatation in the cat dental pulp shows conflicting results, leaving some uncertainty regarding pulpal vascular responses to parasympathetic neurotransmitters.

Neurotransmitters and Vasodilation

Calcitonin gene-related peptide (CGRP) is a neurotransmitter released from sensory nerve fibers, leading to vasodilation.
Glutamate is another vasodilator, present in sensory afferent nerve fibers in the pulp that do not contain CGRP.
Experimental conditions demonstrate that glutamate applied to the pulp induces vasodilation.

Parasympathetic Neurotransmitter and Vasodilation

Acetylcholine (ACh), a parasympathetic neurotransmitter, causes vasodilation, leading to increased blood flow within tissues.
The vasodilation induced by ACh is partially dependent on the production of nitric oxide (NO).

Vasoactive Intestinal Polypeptide (VIP)

VIP is a neuropeptide with potential neurotransmitter function.
It coexists with acetylcholine (ACh) in postganglionic neurons.
VIP is found in the dental pulp.
VIP has been shown to cause vasodilation and increase in blood flow in cats.

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