Neuroendocrinology an integrative approach

Transcription

1 Neuroendocrinology an integrative approach JP Advis DVM, Ph.D. Bartlett Hall, Animal Sciences, Cook, (848) , 04 Course website: rci.rutgers.edu/~advis Material to be covered: Meeting 01: Introduction to Neuroendocrinology (1) Meetings 02-03: How to answer and present home-works #01-#02 (2) Meetings 04-06: How to answer and present home-works #03-#06 Meetings 07-08: REVIEW AND TEST #1 (draft overview of home-works #03-#06) Meeting 09: Stress as a Neuroendocrine alarm sensor (1) Meetings 10-12: Neuroendocrine Control of Reproduction (3) Meeting 13: Stress and the Neuroendocrine Control of Reproduction (1) Meetings 14-15: REVIEW AND TEST #2 (draft answers of home-works #03-#04) Meetings 16-17: Neuroendocrine Control of Hydro-mineral Homeostasis (2) Meetings 18-19: Neuroendocrine Control of Food Intake and Metabolism (2) Meetings 20-21: Neuroendocrine Control of Biological Rhythms (2) Meetings 22-23: REVIEW AND TEST #3 (draft answers of home-works #05-#06) Meetings 24-27: Student oral presentations of their two best home-works (4) Meetings 28-29: REVIEW AND TEST #4 (final answers of home-works #03-#06) 01 Introduction to Neuroendocrinology (1) How to answer and present home-works #01-#02 (2) The circle and this course home-works (3) REVIEW AND TEST #1 (draft overview of home-works #03-#06) 09 Stress as a Neuroendocrine alarm sensor (1) Neuroendocrine Control of Reproduction (3) 13 Stress and the Neuroendocrine Control of Reproduction (1) REVIEW AND TEST #2 (draft answers of home-works #03-#04) Neuroendocrine Control of Hydro-mineral Homeostasis (2) Neuroendocrine Control of Food Intake and Metabolism (2) Neuroendocrine Control of Biological Rhythms (2) REVIEW AND TEST #3 (draft answers of home-works #05-#06) Student oral presentations of their two best home-works (4) REVIEW AND TEST #4 (final answers of home-works #03-#06) Page 1

2 Introducing the circle (part #1) LECTURE #05 LECTURE #06 to a brain CRH integrator, to maintaining homeostasis to brain PVN integrators, to appetite and GI functions to a brain GnRH integrator, to female cyclic reproduction From hydro-mineral signals, to brain-related integrators to cardiovascular, respiratory, and renal function to clock and metabolic integrators. to anticipation and homeostasis From draft homework versions, to exam #01, #02 and # 03, to final homework, abstracts and oral presentations (exam #04) Introducing the circle (part #1) Today s lecture 04 Page 2

3 Introducing the circle (part #1) The Knee Jerk Reflex and the circle concept S E Introducing the circle (part #1) theoretical components! of a feedback! (e.g. the refrigerator )!??? S E Page 3

4 Introducing the circle (part #1) S theoretical components! of a feedback! (e.g. the refrigerator )! variable under control (t F/C)! thermostat (set point)! t F/C detector (feedback)! comparator (integrator)! common language! error signal (on/off)! amplifier and engine! E feedback detector T! E! M! P! E! R! A! T! U! R! E! negative feedback loop set - point comparator error signal amplifier engine controlled variable E! L! E! C! T! R! I! C! A! L!! S! I! G! N! A! L! S! Introducing the circle (part #1) theoretical components! of a feedback! (e.g. the refrigerator )! set point variable under control (t F/C)! thermostat (set point)! t F/C detector (feedback)! comparator (integrator)! common language! error signal (on/off)! amplifier and engine! S E Page 4

5 Introducing the circle (part #1) Questions to be asked about any homeostatic reflex or of the circle as a thinking process Introducing the circle (part #1) Some important generalizations about homeostatic control or of the circle as a thinking process Page 5

6 Introducing the circle (part #1) Examples of an homeostatic control and a driving behavior that can be considered as circles S E Introducing the circle (part #1) Example of how an homeostatic control considered as a circle can be modified by higher regulators -Fb S E Reset control of negative feedback by higher system or a clock Page 6

7 Introducing the circle (part #1) set point afferent story line S sensor integrator center diagram for a control system as that present in a refrigerator negative feedback story line a reflex arc a base for a control model efferent story line E effector if story lines are linked through an integrator and a -Fb, then you have control Introducing the circle (part #1) Final Homework Sub-questions a through f Abstract Intro, THM, lines of evidence, THM S E Paper Presentation Intro, M&M, results, discussion Oral Presentation THM, objective, results, THM, discussion Page 7

8 Introducing the circle (part #1) S E -Fbs Introducing the circle (part #1) story lines and circles intersecting circles S E how many circles do you see here? Page 8

9 Introducing the circle (part #1) S E Joseph-Bravo Patricia (2015). TRH, the first hypophysiotropic releasing hormone isolated: control of the pituitary thyroid axis. Journal of Endocrinology, 60 years of Neuroendocrinology. (see PDF in website). Introducing the circle (part #1) Elements involved in HPT regulation. S E Joseph-Bravo Patricia (2015). TRH, the first hypophysiotropic releasing hormone isolated: control of the pituitary thyroid axis. Journal of Endocrinology, 60 years of Neuroendocrinology. (see PDF in website). Page 9

10 Introducing the circle (part #1) Puberty occurs seasonally in the majority of mammals native to temperate or arctic latitudes, and in species with sufficiently long life spans puberty can be considered to reoccur on an annual basis. The precise timing of puberty and the annual reoccurrence of fertility reflects an interaction of changes in ambient daylength (photoperiod) and endogenous long-term timing processes, which in some species constitute circannual clocks. Recent studies reveal an unexpected common signalling pathway for photoperiodic information in mammals and birds: changes in secretory activity of the pars tuberalis in the pituitary stalk signal to the tanycyte cells in the ependyma lining the third ventricle. The target genes in the tanycytes encode the deiodinase enzymes that regulate the availability of thyroid hormone in the hypothalamus. Central availability of thyroid hormone appears to be the key determinant of seasonal reproductive transitions. Given the necessity of thyroid hormone for the initial development of the central nervous system, it is hypothesized that at puberty and seasonal reoccurrences of fertility it is the changing local levels of thyroid hormone that orchestrate hypothalamic plasticity, ultimately impinging upon the secretion of GnRH. Ebling Francis (2010). Metabolic control of puberty onset: New players, new mechanisms. Molecular and cellular endocrinology. Volume 324, , Introducing the circle (part #1) Example of how an homeostatic control considered as a circle can be modified by higher regulators -Fb S E Reset control of negative feedback by higher system or a clock Page 10

11 -appendix slides- The following slides come from the Integrative Physiology and System physiology courses thought by this instructor (JP Advis). They are presented here as a way to help students review basic prerequisite information. They have been organized by main topics and subtopics, and are included as appendix to most lectures. These prerequisite material will not be presented in the lectures for this Neuroendocrinology course, except for discussion purposes. structure / function relationship Neurons are a functional structure for neuronal communication Page 11

12 Ion channels are a functional structure for neuronal communication Action potentials is the functional unit for neuronal communication Page 12

13 Action potential is the functional unit for neuronal communication Action potential is the functional unit for neuronal communication Page 13

14 electric! chemical! A synapsis is a functional structure for neuronal communication Graduate potentials are the functional unit for synaptic transmission Page 14

15 When a graduate potential reaches threshold it elicits an action potential Stimulus magnitude is coded by the amplitude of the graded potential and by the frequency of the action potential Page 15

16 Miniglossary of terms describing membrane potentials Basic Hormone Categories water-soluble messengers lipo-soluble messengers Hormones are classified as water-soluble or lipo-soluble hormones Page 16

17 water-soluble messengers lipo-soluble messengers Hormones are classified as water-soluble or lipo-soluble hormones Hormones might be stored, secreted, activated or inactivated, and eliminated from the body Page 17

18 Hormones might be stimulated or inhibited by ions or nutrients, neurotransmitters or other hormones The hypothalamus controls anterior pituitary hormone secretion (biosynthesis and release) Page 18

19 ANTERIOR PITUITARY HORMONE SECRETION The hypothalamus controls anterior pituitary hormone secretion (biosynthesis and release) The hypothalamus and the posterior pituitary have the same embryological origin Page 19

20 POSTERIOR PITUITARY HORMONE SECRETION oxytocin! (OT)! Vasopressin! (AVP / ADH)! The hypothalamus and the posterior pituitary have the same embryological origin camp ----> PKA ----> channel / enzyme R AC 5 Na / K pump 3 E1 mrna HRE Protein synthesis XX1 SR Steroid S + R ----> SR SR DNA additional transcription factor The main mechanism of action of water-soluble (2nd messenger) and lipo-soluble (gene transcription) ligands Page 20

21 The mechanism of action of lipo-soluble ligands The mechanism of action of lipo-soluble ligands Page 21

22 The mechanism of action of water-soluble ligands The mechanism of action of water-soluble ligands Page 22

23 The hypothalamus is the director of the endocrine orchestra The hypothalamus is the director of the endocrine orchestra Page 23

24 Vascular supply of the human pituitary gland. Note the origin of long portal vessels from the primary capillary bed and the origin of short portal vessels from the capillary bed in the lower part of the stalk. Both sets of portal vessels break up into sinusoidal capillaries in the anterior lobe. in vivo Stalk transection Kidney transplant Neonate pituitary Harris, Halaz, Yalow Shally, Guilleman half AP + half AP - in vitro ACTH, CRF, CRH TSH, TRF, TRH LH/FSH, LRF, LHRH, GnRH GH, GRF, GRH GIF, SS PRL, PIF, DA PRF, VIP, TRH, 5HT The hypothalamus is the director of the endocrine orchestra Page 24

25 L H release into systemic blood GnRH release into portal blood in vivo release time at 10 min intervals follicular anestrus The hypothalamus is the director of the endocrine orchestra Changes in hormone concentrations in blood may follow different patterns: A.Hourly rhythm of LH secretion. B.B. Daily rhythm in testosterone secretion. C.C. Episodic secretion of prolactin. The hypothalamus is the director of the endocrine orchestra Page 25

26 The hypothalamus is the director of the endocrine orchestra Page 26