Pharmacology Flashcards
Where are cell bodies of preganglionic fibres embedded?
In the brainstem
Where are the cell bodies of post ganglionic fibres embedded?
In walls of the bronchi and bronchioles
What does stimulation of postganglionic cholinergic fibres do to bronchial smooth muscle? what is it mediated by?
It contracts smooth muscle, mediated by M3 muscarinic ACh receptors on ASM cells
True/false, mucous secretion increases after stimulation of postganglionic cholinergic fibres
True
What does stimulation of postganglionic NONCHOLINERGIC fibres cause? and what is it mediated by?
It causes bronchial smooth muscle relaxation, mediated by nitric oxide (NO) and vasoactive intestinal peptide (VIP)
True/false, mucous secretion increases during the sympathetic division
False, mucous secretion decreases
True/false, there is no sympathetic innervation in bronchial smooth muscle?
True
Which interleukins cause mast cells to express IgE receptors?
IL-4 and IL-13
What do activated mast cells release?
Histamines, chemokines, Leukotrienes
In sympathetic division, what happens to bronchial smooth muscle when stimulated?
Relaxation
Which interleukin causes eosinophils to differentiate and proliferate?
IL-5
True/false, mucous secretion is increased when the sympathetic division is active
false, it is decreased as mucociliary clearance is increased
Which adreno-receptor mediates bronchial smooth muscle relaxation and what is it activated by?
Beta2-adrenoceptors (β2-ADR) on ASM cells activated by adrenaline released from the adrenal gland
Which adrenoreceptor mediates decreased mucous secretion?
Beta2-adrenoreceptor on gland (goblet) cells
Which adrenal-receptor mediates vascular smooth muscle contraction?
Alpha1-adrenoreceptors
Where does calcium come from that binds to calmodulin?
From extra-cellular, into the cell through Ca channels and (mostly from) the sarcoplasmic reticulum
What does the release of calcium into the cytosol cause in smooth muscle cells?
Contraction
What happens when GPCR is activated by a transmitter/hormone in smooth muscle?
Phospholipase C is activated by a G protein subunit and it converts PIP2 into IP3 and DAG. IP3 then binds to its receptor on the sarcoplasmic reticulum, its receptor is a calcium channel, so calcium is released into cytosol
What happens that initiates contraction of smooth muscle?
Phosphorylation of the regulatory myosin light chain(MLC) in the presence of elevated intracellular Ca (and ATP)
What has to happen to initiate relaxation of smooth muscle?
Relaxation results from dephosphorylation of MLC by myosin phosphatase which has constitutive activity
What does relaxation require or Ca levels in the cytosol?
Relaxation requires return of intracellular Ca2+ concentration to basal level – achieved by primary and secondary active transport
Which hormone relaxes airway smooth muscles?
Adrenaline
What does cAMP do in cells?
Activates kinases
Which enzyme degrades cAMP to switch off the signalling pathway?
PDE - phosphodiesterase which degrades cAMP into 5’AMP
