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59 Cards in this Set
- Front
- Back
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magnocellular system (4)
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-large neurons
-nissl substance a neurosecretory substance around nucleus and variscosities -mainly secrete OT/VP from two areas-PVN and SON -secrete in response to electrical activity and sensd down axons via axoplasmic flow into posterior pituitary |
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VP/OT neurons of PVN also project to_____for____and also act as _____in brain
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brainstem and spinal cord, for cardiovascular control,neuromodulator
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describe VP, OT, vasotocin structure
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-similar different in site 3,8
-nonapeptides (9aa) -disulfide bonds between cys 1 and 6 -VP has phe on 3 and arg on 8 -OT has iso on 3 and leu on 8 -vasotocin has iso on 3 and arg on 8 |
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higher vertebrates have both OT and VP due to
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gene duplication
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VP/OT come from precursor protein cleaved by PC's. When released they are found with their buddy
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neurophysins which are cystein rich protein (95aa) they are byproducts of cleavage they have no known function.
Neurophysin 1 goes with OT Neurophysin 2 goes with VP They are the parts that get stained in HERRING bodies by GOMORI staining |
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VP/OT gene and precursor protein structure
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-both on one gene each has 3 exons. Hormone seq on exon 1
-signal peptide,hormone seq responsive to thyroid hormone estrogen and retinoic acid, consensus seq (gly-lys-arg) called GKR thats cleaved, rest is neurophysin |
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SON (4)
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-only magnocellular
-neurophysin positive meaning that neurons are either OT or VP projecting into post pit -OT neurons anterodorsal -VP neurons posteroventral |
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PVN is both parvo and magno in magno part the OT neurons are ____and VP neurons are ___. Which is more numerous. The PVN neurons are positive for?
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rostral,caudal/lateral;VP;Enk or CCK
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positive Enk neurons from PVN project into___and therefore involved in
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posterior pituitary where they regulate VP release
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Inputs that regulate magnocellular system in SON and PVN
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-NST:sensory nuclei who's sensory axons in 9th/10th cranial nerve. Have A2/C2 cataecholminergic neurons.
A2 makes noradrenaline. -limbic system relay nuclei -anterior circumventricular organs |
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OT/Vp acts on what receptors?
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G protein
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OTR,V1A,V1B receptors coupled to
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phospholipase C which cause production of inositol triphosphate and 1,2 diacylglycerol
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inositol triphosphate
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triggers Ca2+ release
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1,2 diacylglycerol
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activates protein kinase C
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V2 receptor couples to
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adenylate cyclase which causes increase in cAMP
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OTR (2)
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-7TM G protein
-highly regulated on 3rd intracellular loop/C terminus |
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OT what it does for smooth muscle contraction (3) and for sexual/social behaviours in both sexes (1)
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-during labour for uterine contractions, increases receptors
-stimulates myoepithelial cells of mammary glands to eject milk -sperm transport |
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amking and ejecting milk requires what hormones (5)
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OT,prolactin,cortisol,estrogen,progesterone
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OT released in ___and can be triggered by crying babies
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bursts
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release of OT/VP during pregnancy,parturition,post partum
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OT increases during parturition and during sucking after birth, VP only increases during post partum. So even though VP related to OT dont see changes in VP like you do in OT expression/release
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OT neurons in PVN and input (4)
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NST,SFO,OVLT,limbic system via BST
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during parturition theres coactivation of OT neurons of SON and
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NE neurons.
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NE does what to OT neurons and what experiment showed us this
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modulates them, if you use alpha 1 antagonist NE decreases and also see decrease in OT.
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what other factors modulate OT neurons beside NE
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central opioids, progesterone steroid metabolites
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prairie vole vs montane vole
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prairie vole live monogamously they take part in caring for babies montane voles do not they live heterogamously they dont have parenting behaviours. The level of OT in prairie is higher
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vasopressin release is more sensitive to what cardiovascular stimuli or changes in plasma osmolarity
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plasma osmolality
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central osmoreceptors located in the (3) and peripheral osmoreceptor/baroreceptors give info to brain via____
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SFO,OVLT, wall of 3rd ventricle; 9th/10th cranial nerve
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central processing of info from peripheral baro/osmoreceptors involves these 4 structures
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NTS,area postrema, noradrenergic fibers,median preoptic nucleus
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VP action in kidney
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inserts aquaporins into apical membranes of collecting tubules to reabsorb water from urine
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release of VP regulated also by blood ___and __
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pressure and volume. It is a vasoconstrictor it increase blood pressure
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receptors involved when VP released due to blood pressure/volume changes
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stretch/baroreceptors in aortic arch,carotids,left atrium
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response to hemorrhage
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-decreased blood volume
-drop in BP -two things happen 1)baroreceptors sense this send info via 9th/10th cranial nerve to NTS which sends info to A1(noradrenergic cells in ventrolateral medulla) tells PVN/SON to increase VP and CRH 2)increase in plasma angiotensin 2 which tells SFO to tell PVN/SON to increase VP/CRH |
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____system is involved in regulating VP release
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renin-angiotensin
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renin
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enzyme in glomerulus of kidneys with PC function makes angiotensin 1 into 2 causes vasoconstriction
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see plasticity in magnocellular during ___or___
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dehydration,lactation
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what is the basis to reorganization in magnocellular system
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glial cell plasticity
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under normal conditions astroglial processes; during lactation or dehydration
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seperate magnnocellular somata; processes withdraw allows for direct contact between somatic membrane and dendritic membrane of neighboring magnocell neuron
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VP neurons co-localized with
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apelin, expressed in SON/PVN magnocellular and in ME
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apelin and VP concentrated in
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distinct vesicles in magno neurons
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true or false: neurons VP positive express APJ (apelin receptor)
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true
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apelin
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prodiuretic hormone,it reduces plasma VP levels therefore increases diuresis
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central action of apelin (3)
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-inhibits phasic electrical activity of VP neurons
-inhibits systemic VP release -increases diuresis in kidneys |
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water deprived animals show increase in____and no change in___
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apelin,VP
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when V1 antagonist is given to water deprived see
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decrease in apelin in neurons
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since both dehydration and VP induced apelin pile up seen in magnocellular neurons it suggests
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blockade of apelin release
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the hypothesis for VP release from magnocellular neuons and apelin is that
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VP release impedes apelin release from same cell via V1 autoreceptor
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synaptic vesicles and large dense vesicles docking is the same true or false
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true
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for synaptic vesicle release need and for large dense need
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only one or two AP, titanic stimulation (large stimulus)
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Galen
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pituitary waste product sink not true
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Arnold Berthold
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hormonal action by transplantation of testes
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Marie
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discovers acromegaly
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EH starling
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term hormone
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Harvey Cushing
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pituitary gonadal link, cushing syndrome (ACTH increase)
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Geoffrey Harris
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electrical stimulation of hypo=altering pit hormones secretion
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Berta and Ernst Schaller
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concept of neurosecretion via staining in PVN/SON
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Wolfgang Bargmann
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neural connection between hypo and pit
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Scharrers and Bargmann
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establish substance travels down axons and into post pit
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Saffran,Schally,Guillemin,Rosenberg
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CRF
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Schally,Guillemin
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nobel prize for TRH identification, competitors
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