2020-10-05 13:43:53

Prelude

Announcements

  • Quiz 2 this Thursday, 10/8
  • Blog post 1 (of 3) due this Thursday by 5:00 pm

Today’s Topics

  • Reminder: Quiz 2 this Thursday, 10/7, Canvas 12p-6p.
  • Hormonal communication

Warm-up

Black widow spider venom causes paralysis by impeding the normal function of which neurotransmitter system?

  • Glutamate (Glu)
  • GABA (GABA)
  • Dopamine (DA)
  • Acetylcholine (ACh)

Black widow spider venom causes paralysis by impeding the normal function of which neurotransmitter system?

  • Glutamate (Glu)
  • GABA (GABA)
  • Dopamine (DA)
  • Acetylcholine (ACh)

With one exception, the monoamine neurotransmitters bind to what type of receptors?

  • ionotropic
  • voltage-gated
  • nicotinic
  • metabotropic

With one exception, the monoamine neurotransmitters bind to what type of receptor?

  • ionotropic
  • voltage-gated
  • nicotinic
  • metabotropic

With one exception, the monoamine neurotransmitters bind to what type of receptor?

  • ionotropic
  • voltage-gated
  • nicotinic ACh binds to nAChR; ACh not a monoamine
  • metabotropic

The outward flow of this ion across the neural membrane creates what kind of PSP?

  • Cl-; IPSP
  • K+; IPSP
  • Glutamate; EPSP
  • GABA; EPSP

The outward flow of this ion across the neural membrane creates what kind of PSP?

  • Cl-; IPSP
  • K+; IPSP
  • Glutamate; EPSP
  • GABA; EPSP

The outward flow of this ion across the neural membrane creates what kind of PSP?

  • Cl-; IPSP Outward Cl- -> inside less negative == EPSP
  • K+; IPSP Make inside less positive
  • Glutamate; EPSP Glu not an ion; transported across
  • GABA; EPSP GABA not an ion; transported across

Hormones

Hormones

  • Chemical secreted into blood
  • Act on specific target tissues
  • Produce specific effects

Can a substance be a hormone AND a neurotransmitter?

  • Yes, why not?
  • No, absolutely not.

Can a substance be a hormone AND a neurotransmitter?

  • Yes, why not?
  • No, absolutely not.

Examples of substances that are both hormones and neurotransmitters

  • Melatonin
  • Epinephrine/adrenaline
  • Oxytocin
  • Vasopressin

Behaviors under hormonal influence

Behaviors under hormonal influence

  • Ingestive (eating/ drinking)
    • Fluid levels
    • Na, K, Ca levels
    • Digestion
    • Blood glucose levels

Behaviors under hormonal influence

Behaviors under hormonal influence

  • Reproduction
    • Sexual Maturation
    • Mating
    • Birth
    • Care giving

Behaviors under hormonal influence

Behaviors under hormonal influence

  • Responses to threat/challenge
    • Metabolism
    • Heart rate, blood pressure
    • Digestion
    • Arousal

What do these behaviors have in common?

  • Biological imperatives
  • Events restricted in space and time
  • Often involve other animals

Differences between neural and hormonal communication

  • Point to point vs.“broadcast”
    • Wider broadcast than neuromodulators
    • Everywhere in body via bloodstream
  • Fast vs. slow-acting
  • Short-acting vs. long-acting
  • Digital (yes-no) vs. analog (graded)
  • Voluntary control vs. involuntary

Similarities between neural and hormonal communication

  • Chemical messengers stored for later release
  • Release follows stimulation
  • Action depends on specific receptors
  • 2nd messenger systems common

Where are hormones released

Where are hormones released?

  • CNS
    • Hypothalamus
    • Pituitary
      • Anterior
      • Posterior
    • Pineal gland

Where are hormones released

Where are hormones released?

  • Rest of body
    • Thyroid
    • Adrenal (ad=adjacent, renal=kidney) gland
      • Adrenal cortex
      • Adrenal medulla
    • Gonads (testes/ovaries)

Two hypothalamus/pituitary release systems

  • Direct
  • Indirect

Direct hormone release into bloodstream

  • Hypothalamus (paraventricular, supraoptic nucleus) to
  • Posterior pituitary
    • Oxytocin
    • Arginine Vasopressin (AVP, vasopressin)

Direct release

Indirect release

  • Hypothalamus -> releasing hormones
  • Anterior pituitary -> tropic hormones
  • End organs

Indirect release

Case studies

Case 1: Responses to threat or challenge

  • Neural response
    • Sympathetic Adrenal Medulla (SAM) response
    • Sympathetic NS activation of adrenal medulla, other organs
    • Releases NE and Epi

Case 1: Responses to threat or challenge

  • Endocrine response
    • Hypothalamic Pituitary Adrenal (HPA) axis
    • Adrenal hormones released
  • Hypothalamus
    • Corticotropin Releasing Hormone (CRH)
  • Anterior pituitary
    • Adrenocorticotropic hormone (ACTH)

Case 1: Responses to threat or challenge

  • Adrenal cortex
    • Glucocorticoids (e.g., cortisol)
    • Mineralocorticoids (e.g. aldosterone)

Adrenal hormones

  • Steroids
    • Derived from cholesterol
  • Cortisol
    • increases blood glucose, anti-inflammatory
    • negative consequences of prolonged exposure
  • Aldosterone
    • Regulates Na (and water) retention in kidneys

Case 2: Reproductive behavior – the milk letdown reflex

  • Hypothalamus releases oxytocin into posterior pituitary
  • Targets milk ducts in breast tissue

Milk letdown reflex

Oxytocin’s role

Oxytocin

References

Domes, G., Heinrichs, M., Kumbier, E., Grossmann, A., Hauenstein, K., & Herpertz, S. C. (2013). Effects of intranasal oxytocin on the neural basis of face processing in autism spectrum disorder. Biological Psychiatry, 74(3), 164–171. https://doi.org/http://dx.doi.org/10.1016/j.biopsych.2013.02.007

Weisman, O., & Feldman, R. (2013). Oxytocin effects on the human brain: Findings, questions, and future directions. Biological Psychiatry, 74(3), 158–159. https://doi.org/http://dx.doi.org/10.1016/j.biopsych.2013.05.026