all Flashcards
what are the two mechanisms in the brain controlling stress in mammals?
sympathoadrenmedullary axis - autonomic
hypothalamic piutiary adreno cortical axis - slower resp longer duration
describe the action of the hpa axis in response to stress
stress exposure
paraventricular nucleus of the hypothalamus releases crh and avp
travel via the hypothesal portal system to anterior pituitary
a.pit release ACTH
into blood
to adrenal glands which secret glucocorticoids (cortisol) and calecholamins (adrenaline/nora)
there negative feedback to GR and AR in the hippo/hypo/a.pit in the brain
what do high levels of GR do to stress response?
more negative feedback
suppress response quicker
what effect do excess GC have on CNS?
necrosis/aging neurogenesis morphological changes synaptic plastcity neurochem syst combined effect on learning and memory
describe the experiments in rodent of maternal behaviour and stress
is variation in beahviour
better mother=groom more
offspring better mother lower stress response (CRH mRNA levels and G mRNA level)
better mothers better on morris water maze - better synaptic survival/intelligence
describe the experiments in rodent maternal beahviour and stress determining whether genetic or non inheritance
handle pups = worse mothers groom
handled offspring from bad mothers better groomers to their own offpsirng - e’life inf own mat car
cross foster= bad mum and good foster - low anxiety . good mum bad foster - low anxiety only in bad both - high anxiety - genomic info inv too
what is the role of NGIF-A and serotonin in maternal behaviour
serotonin activate cascade which alters levels of NGIF-A which is a TF
bad mums serotonin level static, no NGIF-A in hippo, methy of GR promoter gene (Nr3cl)
good mum incr serotonin high NGIF-A demthy G gene - incr G expr
describe the role of histone modifications on rat maternal behaviour
bad mums have low levels of active histon marks H3K9ac and H3K4me, chromatin repressive low G expr as pup =adult-higher cortisterone and anxiety
good mums high H3K9ac and H3K4me, marks, incr GR in hippo as pup,a adult lower anxiety and cortisterone
what examples in humans of early life stress imprinting behaviour
holocaust - incr risk PTSDManxitey depr
9/11 - beahvioural problems in preschool
what are the 3 models/hypothesis for stress and behaviour
cumulative stress = positive corr adult/e.life
mmismatch - e.life stress=better able to cope mismatch most sever
3d model-env/ind factors/gen background programme sensitvity
give an example of a genetic polymoprhism influecning adult behaviour
monoamine oxidase
inv in serotonin noradrenaline production
ko maoa - more agrr
maoa promoter polymoprhs control maoa activity
low maoa activity in boys at adol and adult antisoc behaviour
(mal treatment not incr risk of boys with high maoa acti)
is ptsd predisposed by hippo size?
low hippo size indicater ptsd
twin study low hippo size does predispose
what is genomic imprinting
epigenetic phenomemnon
genes expr in parent of origin manner
parental origin specific differential gene expression
describe the mouse experiments that discovered genomic imorinting
create a parthenogenic embryo - x2 mat genome
and a androgenic embry x2 pat genome
pg - impair placenta dev
ag - no embryo just extra embryonic tissue
need both parental genomes for deb
pat genome imp in placenta dev
mat genome imp in fetus dev
what do the findings that both maternal and paternal genomes suggest
that some genomes only from one genome are expressed
what theories are there for the evolution of imprinted gene and brief explain
parental conflict - pat/mat genes have coonflcit interest, mat gene want to reserve resource for future repr output where as pat gene sel favour genes that use resources as in competition / benefit own fitnes
coadaptation - imprint genes act coadaptively to optimise fetal dev and maternal provision
give an example of a imprinted gene that supports the parental conflict hypothesis
Igf2 norm pat expr
pat in placenta extract resources and encourage growth
mat gene codes the igf2r , when igf2 binds - destruction complex reduces the amount igf2
oppose eachother
give an example of an imprinted gene that supports the coadaptation hypothesis
Peg3
norm oat expr
in mother expr in hypo and regulates maternal behaviour and physiology (milk rel and m.care)
in young inv in suckling
KO - imapirmother behaviour and pup growth
komum Wt young - impair mat care
wt mum and ko pup (plac)- impair plac growth/
both result in delay growht and puberty onset - consequence same
what are ICRs
imprini=ting control regions
show parental allele specific DNA methy and chromatin mod
act when unmeth
give an example of methylation controlling expression of imprinted gene
igf2-h19
female expr - DMD/ has bind sites CTCF, when unmethy CTCF bind and prevent enh act of igf2 =h19 expr
male expr - DMDICR methy , CTCF can’t bind - igf2 expr
what the function Dnmt1
enzye in dna methyl mainatenance
what are hte phenotype of mouse chimeras of AG and PG embryos
PG N = large brain, decr body
AG N = small brain big body
suggest again the mat and pat genome have differnet interests regarding allocation of resources
what is turner syndrome
all cells in the body expressing x chr from same parent
what are the differences in cognitive finction depdning on if the X from dad or mum in Turner sydrome
Xm = 40% special needs/ 72% social difficulties
soem gene inv in behavior and social cognition are paternally imprint
siggest the primary mech factor contributing to some of hte se diff between the sexes genetic not hormonal
what is the link autism and imprinting
argued disease of imprinted brain
consequence sucess of pat brain and failure of mat
more prevalent in ppl with turner syndrom 5%
chr 15 imprinting genes and behavior
location on chr 15 lot of imprinted genes
paternal bias in region results in happy puppet syndrome higher incidence of autism
maternal bias - Prader willi syndrome and more risk psychosis
what is the link of autism and psychosis
opposite phenotypes of human cognitions disorders
aut- oergrowth/social cog under dev
psychosis-undergrowth and social cog over dev
what brain parts create the imbalanced adolescent brain
amyglada and nucleus acumbes (NAc) are one of the first areas to develop
inv in emotion / reward
later develops is the pre frontal cortex inv in rationale
what sex steroid inhibit the hpg axis in women and men
prog andT
where is Kisspeptin found in the brain
Arcuate nucleus
AVPV
how to Kp neurone in ARc respind to oestrogen
negative feedback
to terminal body of the GnRH neurone
how to Kp neurone in avpv respind to oestrogen
positve feedback
to cell body
what neuropeptides does AVPV GnRH neurone produce
kiss1
galanine
tyrosine hydroxylase
what neuropeptides does ARc GnRH neurone produce
kiss
neurokinin
dynorphin
what changes occur around puberty ndicate KP imp
incr in kp neurones in hypo and projections to GnRH neurones
incr in Kp tone
incr in GPR54 signal efficieny
incr in sensitivity to the stim effects of KP on GnRH resp
describe the HPG axis in rodents
juveile - an unkown factor activate varies to prod oest - negative feedback and triggers act of HPG act
describe the chnages to the hpg axis activity in humans
infancy Arc GnRH pulse robust, kp release in median eminence into portal circ - lh/fsh rel
juvenile - neruological brake hold arc and gnrh pulse, decr kp rel into me and dec GnRH = hypogonatropic state
pubertal - trigger when break removed and GnRH pulse gen w robust rel of KP in ME react
what are two suggested brakes of the HPG axis in primates
GABA - in rhesus moneky incr at low GnRH anddecr when high, GABA antagonist stim GnRH rel
Neuropeptide y neurons in male monkeys, mrna lower in neonat then juv and decr at puberty
how is Kp shown not to be trigger
metabolic distress, ko saves the repr parametters but no improvment inmetabol related indexes
what suggests leptin ahs role
ko mice = delay puberty when lack of leptin
kiss1 rec in ARc have leptin rec
treatment with leptin partially rescues
what is the role of kp in preganancy
rises throughout preg, x7000 norm by end , fall to norm after delivery - placental source
role in prganancy uncertain
liekly link between the invasive trophoblast
roel of kp in lactation
lactation inh kp syst
decr responsiveness ti kp by GnRH neurones
inh hpg axis
role of hormones in avpv organisation
more kiss in avpv in women
incr t or oest in critical period after nirth masculinse the kiss1 expr
what chnages to hog result in hormonal senescence
decr sex steroids
incr kiss1 in arc incr FSH AND LH
alteration in the hormone conc levels decr in sex steroids signalling = firther decr in Gn
how do gonadal hormones influence the adolescent brain
sensitise the circuits = inf social bbehav /emotion incentic beahviour
sexual mat/sem dim inf brain structure which effects social behav and emotion incentive behaviour
also T slope inf anxiety/depr attention prob
descirbe the mating stucute of gorillas and relate to repr physiology
dom male with harrem
mate once every couple years as long preg and lactation
small testis as no sperm comp
descirbe the mating stucute of chimpanzees and relate to repr physiology
promiscuous
female have pronounced oestus swliing
descirbe the mating stucute of orangs and relate to repr physiology
solitary males
and female soverlap territoires
no overt oestrus sign as solitary
descirbe the mating stucute of bonobos and relate to repr physiology
highly promiscuous
male inherit mums dom status
female overt oestrus sweliing
descrbie the functio of the hyoid bone in the howler monkey
in males larger
lot of variation in sp in size
the more males in the grooup the smaller the hyoid the larger the testis trend
smaller hyoid - deeper call- better intimidation get more mates - less need fo incr testis
what special about the mandril secondary sexual colouring
plastic when becoem/lose alpha status develops
what is special about the marsupial sex determination
have sry like mamals
but also gene dosage imp
one x - scrotum no puch mammary gland
two x no scortum but puch mammary gland
what is snakes sex determination
zw but not hommo to birds
what sex determination in turtles
xx xy of much variety and tsd
what special abouttwo species of the spiny rat
neither have Y chr nor SRY gene cbx2 gene x2 in males cbx2 gene imp in repress ovarian dev in rodent/huuman sp split 2.5mya amami 24 autosomal chr tokunoshuma - 44
what special about two species of mole rat sexual determination
no Y chr lost sry7
maybe gene translocate to x more work needed
what has the red slider shown about tsd and oestrogen
male at low low temp and switch = female low temp and oest or arom= fem low temp and switch and arom inh - male oest core component that activates the female pattern of dev
what has the european pond turtle shown about temp and enzymes intsd
low temp - male mide temp intersex w ovotestis
oest imp, treat w oest male temp - female gonad dev
arom incr at female temp
what is the role of Sox9 in sex determination
in mammals expr when SRY gene expr lead to prod of sertolic cells
in TSH female temp incr oest and armoatas down reg sox9 vice versa
sox 9 act fgf9 w 1+ feedback
fgf9 also inh wnt4 of female pathway
but wnt4 act also inh sox9/fgf9
female no upreg of sox9 not enough fgf9 to repr wnt 4 =wnt 4 repr sox9/fgf9 = female dev
what is the leopard gecko and example of
tsd and effect on behaviour
msle between 30-32.5
lower temp males smaller and less agr have less fem access
what the central bearded dragon a pot eg of
transition between tsd and gsd
have zw syts
but at high temp all zz female
what is the gene important in sex determination in birds
dmrt1
r doses encode male
ko dmrt1 ZZ male develop ovaries w decr sox9
ko dmrt1 zw norm dev
what special about bird ovaries
only have L gonad R regresses
what does the medullary cord become in the sexes of birds
male - seminiferous cord
female - fragment and lacunae
what factor controls showy plummage in birds
genetics
what occurs to the Ra in zebrafinch through the year
breed season incr size
decr in non b season
what controls the sexual dimorphism of the Ra in zebraficnch
at birth exposure to oest - extension of neurones to Ra
if castrtae dim still present - not circulating
oest synth in male brain
birds use locally synthesised oestrogen to differentiate the male brain - gonadal independent
what controls seasonal plummage in birds
in breeding season male have plummage oest blocks this showy plummage if ovarectomise females - showy plummage also in older female birs inject t no effect
what are gynadomorphs
male and femal in one bird
show somatic sex determined by genetic not crculating hormones
but can get beahviour as that induced y circulating hormones
even have lateralised HVC support due to local neurosteroid prouction
what is the sex determination in the duckbilled platypus
male has 5 unpaird copies of 5 diff x like chr and 5 diff y like chr
not homolog to eutherian
closest to chicken z
what does the sex xhromosomes in the monotreme suggest
that xy of therian mammals recent w
in ladt 160my and not 310 my when the split from the bird was as previously thoought
what do monotremes have sort of subsitute of SRY gene
have sox3 autosomal
gene dsage suspected in the monotreme
what is sexual mimcry?
when one sex resemble the other
what sexual mimcry features does the hyena have
pseudo scrotum made from fused labia
penile clitors and no distal vagina
has no tunica unlike the male as have to be elastic
effect of hormones on sexual mimcry in hyena penile citoris
little effect of ovariestectomy at 4-7 month on length but decr elastcity in females
aromatase inh in preg result in male penis more elastic and female clitoral hypospadias
what problem in mating and birth in hyena
mating req coop as female mate through peniform clit
change occur at puberty of enlargin and retractor muscles developing
60cm length pup to travel um cord 12 cm
anoxia common
60% tiem still born
9-18% mother die first born
hypothesis for the ev sexual mimcry
competition aggression
male infanticide
siblibide
matrilineal
does the competition aggression hypo explain sexual mimcry in hyena
agr fem more dom better repr succes
any mut selected for
more agr mum more agr pup
do horomones expain sexual mimcry in hyenas
during preg experience androstenidone
converted to T by enz
mut in aromatase gene
male and femla experience the same amount T
block t in males - fem penis cant mate/brian dimorphic
in females peninfrom forms modified morph thicker and more elastic beeter surv of young
suggest an androgen independent formation although morpho modulateed
what evidence is there in hormones and agression in female hyenas
alpha female offspirng sons x2.5 more androgen and daugh x2.75
pups are more aggr when exposed to more andro
masc genitalia as a by product of agr incr that facilitate fitness
what other animals show sexual mimcry
elephants - hypertrophied litoris resembles male penis but not canalised by uretha
european moles -ovotestis ovaries in breeding season and testicular tissue dev in non b also have enlarged peniform clitoris
peniform clit also in 4 sp of new world (but no ovotestis)
spanish mole - ovotesits change due to T level
flat lizard - young male art resemble female
summary hyena
maternal androgen and ffsprign behav fits link
but block maternal androgen doesnt reverse otype
suggest primary mech at play
what does the mullerian duct dev into
fallopian tube
what experiment showed the testis release something to stimulate wolfian duct
jost experiment
transplant testis onto ovary
wolfian duct stim , ovary rel something (T)
also rel MIH , stop the mullerian duct dev triggers its degen
what sexual differentiation occurs in the early of mammals
SRY expr in germ cells sertoli cells differentiatedwk 7 s cells support germ cells and signal for leydig cell to rel T T rel from leydig cell, act sex diff sertoli cell fsh bind rel androgen bip leydig cell lh bind prod T
whats show the xx xy syst has x linked dosage mech
xo no follicle germ cell die
when is the early embryo got genital diff
week 9 (leydig cells act wk8)
what ptypoe of male castrate
no body hair small penis no androgen
what ptype of xxy
loe t
small testis
limited b dev and little body hair
no w/m duct no sperm
what is the phenotype of xy disgenesis
X linked supr of sRY under dev fem appearance no tesits or ovaries (dev but shrink) uterus vag norm no secondary sexual char as no sex ster
what is the phenotype of testicular feminisation
no AR big breat no uterues vagina short and blind end no testis descenf although intact aromatase no masc behaviour (not as imp in himans?) live as females
what are guevedoces deficient in
5 a reductase
no DHT in dev
at puberty T rise enough for testis to descend
what can the effect of pregnant women androgen
virilised baby
congenital adrenal hyperpllasis genetic females can have oheotyp of between male and female
what problem can luteoma cause in preganancy
secrete androgens cause virilisation
what experiments showed that there was some sexual brain differentiation
ovary transplant onto eye capsule rat - only fem ovulate
60s piuitary transplatn = no sex diff (suggest thhe diff in hypo
describe the lordosis experiment sthat show brain differentiation
ovarientomy - no lordosis
ovariectomy then mimic hormone - lordosis (pried by hormonal history)
repeat in male - no effect (sexes brain diff)
expsoe guinea fem to T pren natal then repeat hormone reg = no lordosis
early androgens permenantyl alter brian
what ev there that androgen not organise the brain
oest more ptent than testo in male brain
inject oest same effect as inject T
radiolabel T end up as radiolabel O
what the role of alpha fetal protein
protect fetus from mat oestrogen
binds to oest and cant move through placenta barrier - prevents entering the brain and masc
males T bypass this system
KO AFP males no effect female - defem
inject oest can swamp system and artificial can pypass
what differnces of SDN POA in the sexes and what causes
in rats males bigger same number of cells derived but female reduce by apoptosis inject oest into female wont occur, sensitive d3-d10 post natal after this little effect
what differnces of MePD in the sexes and what causes
in rats bigger in males medial amyglada
responsive to T throughout life
castrtate decr to fem size in 30 days
x1.5 in males
what differnces of AVPV in the sexes and what causes
bigger in females
T induced apoptosis in males
T cause AVPV neurone to rel chemoattractant that establish teh sex dimorphic innervation pattern
mice over expr bcl2 anti apoptopic gen decr sex dim in Mepd and AVPV
what differnces of HVA AND RAin the sexes and what causes
songbirds
bigger in males
canaires treat wiht T incr size
zebra finch RA bigger in breed season oesst expusre makes the neurones reach RA
castrate - no effect (not circ hormones)
treat female hatchling with oest and T masculine the HVC and RA and induce singing
is T induced behaviour
but local neuorsteroid production brain parts dev
what anatomical brain diff in the sexes in humans
splenium part of caudal corpus callosum more bulbous in fem
what the diff in SNB in sexes and what role
spinal nucleus of bulbocavernous
present in both male and female at birth
T cause neuroe dev and prevent apoptosis in males
T induce muscles to produce a trophic factor (ciliary neurotrophic factor, CNTF) that preseves muscle nd motor neuron
T spare sSNB secondarilt to prevent apop of he target muscle
no CNTF in male still SNB/ no CNTF rec a subunit no SNB / another factor bind to retain SNB
what are the three zone of the hypothalmus
lateral medial periventricular
where are the neurosecretory cells in the hypo
PV
what is the hypothalami portal system
connect the hypo and a.pit
imp for hormone
has fenestrated cap
hypothesal portal vein connects
what role of the posterior piuitary
collection of axonal projection
secrete oxytocin and vasopressin
only store hormone no production
describe ovotestis
bipolar gonads with features of ovaries and testis
testis like region with interstitial tissue and interspersed medullary cords (OIG)
ovarian follicle and OIG At different regions/poles
what hapeens to ovotestis in eurpoean mole and what controls this
vary seasonally in size and endocrine activity
follicular enlarges at secual maturity and at breeding seasons while interstitial regress
reverse at end
T most from OIG rises outside breed season
phallic length larger in females
describe the morphology of the North American moles
Broad and Coast moles norm and have peniform clitoris
the phallic length of the broad foot doesnt differ much from males
starnosed - phallic and bipolar ovaries similar
shrew mole intermediate of bipolar and normal and phallic length
evidence that genitalia of european mole androgen dependent
phallic length males larger than females
treat preg female with T, difference disappper (Godet, 1946
what androgen exposure in utero in hyenas
androstenidone from maternal ovary is converted to oest and T by plac and transferred to dev fetus
what important about observation of penile clitoris formin in hyena at D36
prior to differentiation of the ovaries (what mech therefore drives)
what the effect of removal of external genitalia (ovarectomy / castration) in hyenas
reduces T to v v low
reduces androsteniode to 90%
removal of had little effect on morphology (lenght or number of spines)
non- andro at work?
what the effect of pre-natal anti androgens in hyena?
male - feminised penis (shorter/thicker/diameter and elasticity of the urethal meatus incr) - alll more sim to the female
Female- clitoris broader and shorter urogenital meatus more elastic/ clitoris broader and shorter/ urogenital meatus more elastic
what evidence is there that the creation of the penile citoris in hyena is androgen independent
appear before differnetiation of ovary
survive in utero anti androgen treatment
it morpho is unlike androgenised penis
what evidence is there that the sex differences male and female genitalia in hyena is dependent on secretions from fetal testis
pathways for androgen synth appear in fetal testis before fetal ovaries and conincides with penis dev
anti androgen in utero treatment feminises the penis
evidence that the femal penile clitoris of hyenas is androgenised in utero
anti androgen treatment in utero feminises the penis more (incr size and elasticity of urogenital meatus and decr length)
