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Exam Review for PSY290

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University of Toronto Mississauga
Emis Akbari

Hormones General Principles of Hormone Action 1. Act gradually 2. Change probability or intensity of certain behaviours 3. Reciprocal relationship between the environment and the quantity and types of hormones 4. Behaviors can be affected by a variety of hormones, or a single hormone can act on different behaviours 5. Produced in small quantities and released in a pulsatile fashion 6. Circadian clocks control hormone systems 7. Actions of one hormone can be changed by interacting with another hormone 8. Hormones are similar across vertebrates, but their function may vary across species 9. Hormones effect only cells that contain appropriate receptors and the same hormone receptors are located in the same brain areas in different species Hormone vs. Neural Communication: Differences 1) Neural communication has a fixed destination 2) Neural messages are rapid (ms) – hormonal are slower 3) Neural are all or none – hormonal are graded in strength 4) Differ in voluntary control Similarities 1) Both are stored and released by glands & neurons 2) They both activated second messengers after they bind to the receptors causing changes within the cell Classification of Hormones 3 categories of hormones: 1) Protein Hormones: made of strings of amino acids – if it is short in length it is referred to as a peptide hormone (ACTH, FSH, LH) 2) Amine Hormones: simpler in structure and consist of one amino acid and are sometimes called monoamine hormones (adrenaline) 3) Steroid Hormones: composed of 4 strings of carbon atoms that are interconnected 2 Types: A) Gonadal (estrogen & testosterone) B) Adrenal (cortisol) Synthesis of Steroid Hormones Dihydrotestosterone (through 5-a reductase) ++Testosterone into oestradiol by aromatase The Pituitary • Consists of 2 parts • Anterior pituitary (adenohypophysis) & the posterior (neurohypophysis) • Completely separate in function • Located under the hypothalamus it is connected to it by a thin tissue = pituitary stalk Posterior Pituitary • Stores and releases Oxytocin & Arginine Vasopressin (AVP) • Hypothalamus produces these hormones • Transported to the posterior pituitary from pituitary stalk • From the posterior pituitary they are released to enter the circulation • AVP: related to thirst & water regulation Increases blood pressure Inhibits formation of urine Conserves water • Oxytocin: triggers milk let-down • Both have been implicated in social behavior Anterior Pituitary • Hormones released here are under the control of releasing hormones from the hypothalamus • Anterior pituitary secretes 6 main hormones: • LH: stimulates testes to produce testosterone, the ovaries to produce eggs, and uterus to prepare for implantation • FSH: stimulates ovulation, and sperm production in testes • TSH: stimulates thyroid to produce hormones • ACTH: stimulates adrenal cortex to release hormones • Prolactin: milk let down • GH: general body growth Gonads The Testes: within the testes are sperm producing cells (Sertoli Cells) and Leydig cells that produce and secrete a sex steroid testosterone (an androgen) – production is controlled by LH from anterior pituitary LH in turn controlled by GnRH (hypothalamus) • Controls body changes such as puberty (hair growth, voice change, genital size) • As men age testosterone declines Ovaries: Produce eggs (ovum) and sex hormones • More complicated than testes – cycles • Human ovarian cycle (menstrual cycle – 28 days / estrous cycle – 4 days) Adrenal Glands (On top of Kidneys like a hat) CORTEX • Produces Mineralocorticoids (i.e. aldosterone) – acts on kidney to retain salt and reduce amount of urine produced (zona glomerulosa) – long term regulation of blood pressure. When renal blood pressure drops – body releases angiotensin – causes release of aldosterone • Produces Adrenocorticoids (i.e. Glucocorticoids) – accelerates breakdown of protein, has anti-inflammatory effect, high levels can destroy brain cells (stress) – produced by zona fasciculata . Main Glucocorticoid is cortisol – released basally as well as in burst in response to ACTH • Produces sex hormones (i.e. androstenedione –precursor to Testosterone) – from the zona reticularis - over-activity causes Congenital Adrenal Hyperplasia. MEDULLA • Releases adrenaline (epinephrine) & noradrenaline (norepinephrine) CAH refers to any of several autosomal recessive disease that results from mutations of genes that mediate the biochemical steps of production of cortisol from cholesterol by the adrenal gland. Girls are masculinized because the adrenal glands secrete large amounts of androgen during prenatal development. The extra androgen does not affect a baby boy's physical development, but in baby girls it can enlarge the clitoris so that it resembles a penis. During childhood and adolescence, girls with CAH prefer masculine activities and male playmates to a much greater extent than girls not exposed to these amounts of androgen. Thyroid • Regulate growth & metabolism • Located below vocal cords • Stores huge amount of hormones and releases it slowly 1) Thyroxine - metabolism 2) Triiodo-thyronine - metabolism 3) Calcitonin – promotes calcium deposition in bones Study of Male Sexual Behaviour - History Long known that castration eliminates mating in most species • something in testes regulates sexual behaviour • through 1800s – seminal vesicle swelling activates behaviour Steinach (1894) – remove seminal vesicles of rats • had no effect on mating • must be something else in testes Brown-Sequard (1899) – inject homogenized dog/pig testes • reported restorative powers - energy, libido, stamina Stone (1922) – first real examination of sex in male rats • rats first copulate at 50 days old • still copulate for 14 days after castration Male sexual behaviour in rodents: Divided into two phases 1) appetitive phase • behaviors used to gain access to females • fighting, advertising • communicates how good a mate the male is 2) consummatory phase – actual copulation: three components: 1) mounting - assuming a copulatory position 2) intromission – penis entering vagina 3) ejaculation – expulsion of semen -can’t see; determine behaviorally Can measure frequency or timing of these • Mount, intromission, ejaculation latency • Inter-mount interval (IMI) • Inter-intromission interval (III) • Post-ejaculatory interval (PEI) Testosterone  Testosterone is necessary for the initiation of all consummatory components of male sexual behavior  Castration results in abolishment of mounts, intromissions and ejaculations, while its replacement reverses these effects in both recent and long-term castrates  Testosterone levels increase following exposure to an unattainable receptive female and following copulation  Manipulations that reduce circulating testosterone levels such as chronic ethanol exposure or neonatal treatment with an anti-estrogen result in impairments of male sexual behavior and reproductive function.  These effects can be attributed in differences in androgen threshold Castrate males – reduced sexual motivation (investigate or work for it) - and reduced performance (copulation fades) • first, longer time to mount • then lose ejaculation, intromission, then mounts Rat penile erection • spontaneous reflexes disappear after castration • androgens alone do not elicit erection and other reflexes • must be a stimulation, too • skin sensitivity highest with Dihydrotestosterone injection Aromatized to estrogen and maintains sexual behaviours in castrated males -Testosterone, Androstenedione, and estradiol- NOT DHT Main point: • testes secrete testosterone • T aromatized to estrogens and act on brain • T reduced to DHT to act on periphery Brain Areas Regulating Male Sexual Behaviour • Medial Preoptic Area (MPOA) - hypothalamus • lesions eliminate copulation • sexual motivation intact, though • do not affect non-contact erections • *electrical stimulation – accelerates ejaculation • *measure natural electrical activity – female odors increase • *castration decreases activity in response to odors • *T replacement restores • Medial Preoptic Area (MPOA) • Site of hormone action • T implants in castrated males increases copulation • E implants also work • T implant + aromatase inhibitor – no copulation • T must be converted to E • however, AR antagonist in MPOA also inhibits • must need both ER and AR activity Sites of high AR/ER density in rat brain Note: aromatase also detected in these same sites What do MPOA lesions do that disrupts copulation? • may primarily affect dopamine neurotransmission • Dopamine? • sensory cues from females increases DA release -in MPOA and other sites that receive DA input Olfactory input • needed for sex • two types of olfactory inputs • 1) volatile - olfactory bulbs (MOB) • 2) non-volatile – vomeronasal organ (AOB) • olfactory bulbectomy impairs motivation and performance • effects may be due to decrease in arousal • shock or tail pinch temporarily activates copulation • VNO lesion alone impairs or eliminates performance may be more important than main olfactory input • bulbectomy eliminates both, but VNO alone effective • However, these effects are ONLY seen in naïve animals • Once a male gains sexual experience, olfactory disruption does very little • **Importance of Experience on Brain Plasticity** Amygdala • emotional regulation • receives sensory inputs, integrates for social behaviours • basolateral lesions – reduce motivation undefeatable • corticomedial lesions – increase ejaculation latency (rats) • eliminate copulation (hamsters) • Hormones not always enough to stimulation copulation • influences from environment • social cues very important 1) Coolidge Effect • enhanced mating in sated males if new female presented 2) Mating in nature • not at all like most laboratory tests • usually multiple males/females mating together • females in control of pacing • receive fewer intromissions, at a slower pace • vaginocervical stimulation during paced mating different • optimizes reproductive function, ensures implantation • “vaginal code” 3) Stimulus value (attractivity) of females differ depends on age, hormonal status Individual differences in sexual activity in rodents: • once thought that it was due to differences in T • castrated and retested • low group stopped mating first • all given back same dose of T • behavior went back to original levels, not the same level • animals do not differ because of differences in T • differences reflect differences in target tissue sensitivity • AR/ER content in MPOA Alcohol inhibits and disinhibits sexual behavior in the male rat The Development of Olfactory Conditioned Ejaculatory Preferences in the Male Rat I. Nature of the Unconditioned Stimulus RATIONALE - Do male rats show selective mating? EXPERIMENT 1 – Sexually trained males (intromissions only) with either almond odour or no odour – tested in a triad EXPERIMENT 2 - Sexually trained males (ejaculation) with either almond odour or no odour – tested in a triad EXPERIMENT 3- Sexually trained males (PEI) with either almond odour or no odour – tested in a triad Conditioning and Sexual Behaviour • How strong is the motivation to have sex???? • Pfaus et al. found that an initially aversive stimulus paired with copulation can acquire conditional appetitive properties. • Cadaverine – an airborne polyamine given off by decaying flesh and is innately aversive to rats • Males were either paired with cadaverine scented (C + E) females, Estrous females (E) or habituated with cadaverine prior to testing (C) • Cadaverine acquired conditional appetitive properties • Peters, 1983 • Learned aversions to copulation??? • Male rats received lithium chloride injections immediately after a sexual encounter • First not affected • Eventually after 5-10 trials of pairing, male rats developed aversions and stopped copulating entirely • Persisted after males placed in a novel environment and extinguished after 4 non-reinforced trials Male-Female Mouting Early determinates: - chromosomal sex - gonadal sex - hormonal sex - morphological sex 1. In a variety of species mounting behavior is observed. 2. Mounting in mammalian species is thought to be a sexually dimorphic behavior that males exhibit during mating. 3. As a sexually dimorphic behavior, mounting is thought to be mediated by male/female differences in the brain. Under this hypothesis, the organization of the sexually dimorphic brain results from: HORMONAL AND BIOLOGICAL Δ between the sexes. WHAT DETERMINES WHETHER AN ANIMAL POSESSES: A functional neural circuit to mediate MOUNTING.? During early developmental critical periods a cascade of events determine the development of the sexually dimorphic brain. It is through this organizational process that brain dimorphisms mediate different mating profiles (e.g. mounting males, lordosis females). Extra stuff for Emis-- However does mounting remain in the female brain. Well several species mounting in the heterosexual dyad is displayed by females FMM but males do not submit to being mounted so rarely studied empirically of course. In Rats  Female rats display Female FM throughout their estrous cycle.  FFM decreases when males are present.  Ejaculation or vaginocervical stimulation inhibits FFM.  Socially dominate females mount more than subordinate females  . FFM in mammals has been shown to be used: 1. sexual strategy to obtain mates (e.g., pigs) 2. to gratify a sexual need (e.g., Japanese macaques); 3. in a nonsexual manner (e.g., establish dominancy, rats). In some species, female mounting is a sexual behavior (Vasey, 2007). In rat species, female mounting is not considered a sexual behavior (Fang & Clemens, 1999a, b). However, female mounting of sexually sluggish male rats has been suggested to be a sexual behavior (Beach, 1968). FEMALE-MALE MOUNTING (FMM) in the rat. FMM was increased during proestrus: a period during the estrous cycle when female sexual behavior is observed. SUMMARY: Hormonal and Experiential FMM is: - a robust sexual behavior in females. - mediated by estrogen. - affected by distal (e.g., olfactory) cues from males. Sexual Behaviour in Humans Kinsey reports (1940s) - descriptions of male sexual responses • not quantitative, just descriptive in humans, two components • sex drive/libido (appetitive) • sexual performance/potency (consummatory) • hormones probably necessary for both no universal sexual position • face-to-face most popular • woman on top facing man most common • North America/Europe – man on top more common • man entering from behind offers least clitoral stimulation Role of testosterone • sexual activity begins at puberty • 13.5 years old for boys in N. America • 17 years old for average first intercourse • sexual activity peaks during 20s, then declines • lots of individual variation, though • levels of circulating T parallels sexual activity over age However, effects of castration vary: • in general, half stop all sexual activity • gradual decrease in 25% (over years) • no effect in 10% • age at castration a factor • very young and very old men most affected • Exposure to females increases testosterone • Exposure to pregnant women and babies __________ testosterone SSRI’s and Sex • Those with depression often prescribed SSRIs • Side Effects? Anorgasmia (75% of patients) Loss of sexual desire (20-40%) SSRIs increase ejaculation latency in those with premature ejaculation Decrease desire in certain paraphilias Erectile dysfunction does not occur • Drug Holidays……risk of suicide • Why? Oxytocin • chronic SSRI treatment alters sensitivity of Oxytocin neurons • We see a natural increase in OXY during sexual stimulation in both males and females • OXY given systemically, increases sexual behaviour in females and males and antagonists disrupt it • Giving OXY to males on SSRIs reverses it’s sexual deficit side effects (Cantor & Pfaus) Paraphilias A family of persistent, intense fantasies, aberrant urges, or behaviors involving sexual arousal to nonhuman objects, pain or humiliation, children or other non- consenting individuals or unsuitable partners May interfere with the capacity for reciprocal affectionate sexual activity Also used to imply non-mainstream sexual practices without necessarily implying dysfunction or deviance Optional Vs. Preferred Vs. Exclusive According to DSM The activity must be the sole means of sexual gratification for a period of 6 months, and either cause clinically significant distress or impairment in social, occupational, or other important areas of functioning, or a violation of consent to be diagnosed as paraphilia Exhibitionism: The recurrent urge or behaviour to expose one self to an unsuspecting person Voyeurism: The recurrent urge or behaviour to observe an unsuspecting person who is naked, disrobing or engaging in sexual activities, or may not be sexual at all. Frotteurism: The recurrent urge or behaviour of touching or rubbing against a non-consenting person Fetishism: The use of non-sexual or non-living objects or part of a person’s body to gain sexual excitement * Partialism Pedophilia: The sexual attraction to prepubescent pr peripubescent children Masochism: The recurrent urge or behaviour of wanting to be humiliated, beaten, bound, or otherwise made to suffer Vincilagnia: Being sexually aroused by bondage Sadism: The recurrent urge or behaviour involving acts in which the pain or humiliation of the victim is sexually exciting Transvestic Fetishism: The sexual attraction to the clothing of the opposite gender Treatment chemical castration • CPA – androgen receptor blocker • MPA – reduces T production by reducing LH • effective in reducing paraphilias • self-reports • does not reduce erection from erotic slides • may reduce fantasies Rapists vs. non-rapists • both aroused by scenes of consensual sex • both aroused by simulated rape if woman seems pleasured • only rapists aroused if woman in pain or suffering WHY • rapists believe that victims derive pleasure from assault • insensitive to cues given by women • think that neutral or negative cues indicate receptivity • castration ineffective • more than half of normal castrated men will still copulate Female Sexual Behavior th Relatively little known until 20 Century • lack of interest? • social biases? • too complex? • cyclic; ovariectomy difficult First fact known – removal of ovaries stops mating • how do ovaries influence female sex behavior? • need to know what ovaries do, when they do it • remove ovaries and look at microscopically • need to follow estrous cycle non-invasively • Unlike males, most females not always ready to mate • In many rodents, this cycle occurs every few days • In many larger animals, this cycle occurs seasonally Estrous Cycle Vaginal Cytology Assay (1917) • cells types found in vaginal lining vary according to ovarian function • gently swab vagina • smear on glass slide • stain cells • look at under microscope In rats, cell types cycle every 4-5 days: estrus – cornified (crunchy) epithelial cells  don’t
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