The failure of fentanyl to degranulate
mast cells and antagonism of the fentanyl wheal and flare responses by naloxone led Levy et al (69) to suggest that the fentanyl-induced skin reactions are the result of direct opioid-mediated capillary vasodilation, unlike morphine's effect, which involves both histamine release and a direct opioid effect and therefore, "attempts to antagonize the adverse haemodynamic effects of histamine-releasing opioids with antihistamines will not be completely effective due to direct vascular responses".
Mast cells degranulate
and inflammatory mediators are released, which induce contraction of the bronchial musculature and promote airway narrowing.
They have proposed that this PRP-based membrane could serve as a short-acting biologic barrier, since all platelets contained in PRP will degranulate
within 3 to 5 days, and their initial growth activity expires within 10 days.
Diesel exhaust particles directly induce activated mast cells to degranulate
and increase histamine levels and symptom severity.
4] stimulate monocyte chemotaxis and adherence, these cells do not degranulate
or release reactive oxygen species in response to lipoxins, suggesting that the actions of these lipoxins are specific for locomotion and may be related to the recruitment of monocytes to sites of injury.
In one of the HLH subgroups with normal perforin levels, syntaxin-deficient patients, it was shown very recently that their NK cells failed to degranulate
when they encountered susceptible target cells [16,17].
Mast cell tumors that degranulate
, causing a local erythema and wheal formation when manipulated, are referred to as having a positive Darier's sign.
Collagen provides binding sites for platelets, which degranulate
, releasing coagulation factors and initiating the clotting cascade.
During hemodialysis, polymorphonuclear cells and platelets degranulate
, a process that is thought to be calcium dependent and can be abolished by citrate anticoagulation (13).
Basophils have a nuclei size similar to eosinophils, however, when activated, they degranulate
and release cellular components, including histamine and proteoglycans, stored within the granules, along with proteolytic enzymes.
During hemostasis, platelets aggregate and degranulate
, activating blood clotting.
Resident cardiac mast cells degranulate
and release preformed TNF-alpha, initiating the cytokine cascade in experimental canine myocardial ischemia/ reperfusion.