自主神經系統及下視丘

Autonomic Nervous System

Hypothalamus

Principle of Neuroscience (第五版Ch 47)

楊靜修 老師

Sympathetic NS:

energy-consuming

1. Decrease GI

2. Increase HR, BP

3. Bronchi relax

4. Blood glucose increase

5. NE, Epi release increase

Sympathetic nervous system

Parasympathetic NS:

gain and conserve energy for

the body

1. increase secretion & motility

(salivary gland, GI)

2. decrease HR

ANS (屬PNS但可反應CNS)

-大腦的天線 (接收訊習)

-將大腦訊習傳給全身臟器(ANS可以反應大腦許多功能及問題，所以有機會為biomaker) Parasympathetic nervous system

Reflex arch of autonomic nervous system

CNS: central nervous system

CNS

Visceral

receptors

Afferent autonomic

pathway

Efferent autonomic

pathway

Visceral

effector

integrated

stimulation

Figure 49-1 Anatomical organization of the somatic and autonomic motor pathways.

+

+ or -

Anatomy

IML: intermediolateral horn

Figure 49-2 Anatomical organization of the sympathetic preganglionic and postganglionic axons.

C fiber

交感神經: IML: intermediolateral hornIML--para v.c. 換cell--回spinal nerve (8%) 分泌ACh

--分支出去分泌NEIML--pre v. 換cell--分泌NEIML--adrenal medulla--分泌NE

S2-S4

T1

L3

22對

75%

8% ACh

其他為NEACh

1.分布較少2.反應較不連續且為局部作用

Summary

Autonomic Nervous System• Sympathetic nervous system:

– Spinal nerves T1-L3

• Parasympathetic nervous system:

– Cranial nerves III, VII, IX, X

– Spinal nerves S2-S4

• Enteric nervous system:

– Myenteric (Auerbach’s) plexus

– Submucous (Meissner’s) plexus

Physiology

Transmission Process

Biosynthesis of Neurotransmitters (NE)

Biosynthesis of Neurotransmitters (ACh)

Mechanisms of signal transduction

ACh receptorsNicotinic receptor: N receptor

Muscarinic receptor: M receptor

NE receptor: Adrenergic receptor

ANS(Autonomic nervous system)

Sympathetic

nervous system

Parasympathetic

nervous system

a1-receptor:

contraction BP

b1-receptor:

HR

contractility

b2-receptor:

relaxation

M2 receptor

短

短長

長

Involuntary command: Emergency!

M o t o r n e u r o n

Involuntary command: Rest & digest.

Voluntary command: Move!

以作用到的receptor種類決定何種反應

CNS

Prejunctional autoreceptors

Biosynthesis of Neurotransmitters (NE)

In terminal

Rate limiting step

In vesicle

Tissue, blood, urine可檢測濃度

MAO: monoamine oxidase

COMT: Catechol-O-methyl transferase

Biosynthesis of Neurotransmitters (ACh)

In terminal

合成之酵素choline-O-acetyltransferase

degradation

Mechanisms of signal transduction

Neurotransmitter receptors in the peripheral ANS (adrenoceptors)

Neurotransmitter receptors in the peripheral ANS (cholinoceptors)

Prejunctional autoreceptors

S2-S4

T1

L3

1. 不完全什麼臟器都有兩者控制2. 興奮及抑制都有

HR 以副交感影響為主

副交感系統過度興奮並不好但是維持生存所必需

Autonomic neurons use a variety

of chemical transmitters

• Ganglionic transmission involves both fast and

slow synaptic potentials

• Norepinephrine and acetylcholine are the

predominant transmitters in the ANS

• ATP and adenosine have potent extracellular

actions

• Many different neuropeptides are present in

autonomic neurons

Figure 49-6 Both acetylcholine (ACh) and a luteinizing hormone-releasing hormone (LHRH)-like

peptide are released by presynaptic cells at synapses in the sympathetic chain ganglia in

the bullfrog. The two transmitters produce different types of postsynaptic potentials in

different postganglionic neurons because of their actions on different receptors. .

A central autonomic network

coordinates autonomic function

Central autonomic network

ANS

sympathetic NS parasympathetic NS

Baroreceptor reflex

Brain stem and spinal circuits

Neuronal Regulation of Cardiovascular SystemBaroreceptor Reflex Response (BRR)

vasomotor

center

tonic excitation

交感神經系統 副交感神經系統

Figure 49-9 Pathways that distribute visceral sensory information in the brain.

Figure 49-10 Pathways that control autonomic responses.

Autonomic pharmacology• Ganglionic blockers (transmission and receptor)

-block sympatheric and parasympathetic nerve activity (other factor)

• Drugs that inhibit synthesis of neruotransmitter

• Drugs that inhibit release of neruotransmitter

• Drugs that promote release of neruotransmitter

• Drugs that interfere with storage of neurotransmitter

• Drugs that affect neuronal uptake

• Drugs that inhibit metabolism of neurotransmitter

• Drugs that block autonomic receptors

• Drugs that stimulate autonomic receptors

Adrenoceptor-activating drugsAdrenoceptor-antagonist drugsChlinoceptor-activating & chlinesterse-inhibiting drugsCholinoceptor-blocking drugs

Drugs that inhibit synthesis of neruotransmitter

Drugs that inhibit release

of neruotransmitter

Drugs that promote release of neruotransmitter

Drugs that stimulate autonomic receptors

Drugs that interfere with storage of neurotransmitter

Drugs that affect neuronal uptake

Drugs that block autonomic receptors

Drugs that inhibit metabolism

of neurotransmitter

• Adrenergic transmission:

Uptake

Drugs that inhibit release

of neruotransmitterDrugs that promote release

of neruotransmitterDrugs that stimulate autonomic receptors

Drugs that interfere with storage

of neurotransmitter

Drugs that affect neuronal

uptake and inhibit synthesis

of neruotransmitter

Drugs that inhibit metabolism

of neurotransmitter

Drugs that block autonomic receptors

• Cholinergic transmission:

Effects of drugs:

mechanism

The Hypothalamus Integrates

Autonomic and Endocrine

Functions With Behavior

‘head ganglion’ of ANS

Hypothalamus:

內分泌系統之控制中樞飽食中樞, 飲水中樞, 體溫調節中樞, sexual behavior & 血壓調控,

sleep/wake, circadian rhythms

Neuroendocrinology

Hypothalamus

Anterior pituitary

Posterior pituitary

Homeostasis

HypothalamusNervous system

Pituitary gland

Internal condition

External environment

• It controls blood pressure and electrolyte composition by a set of

regulatory mechanisms that range from control of drinking and salt

appetite to the maintenance of blood osmolality and vasomotor tone.

• It regulates body temperature by means of activities ranging from

control of metabolic thermogenesis to behaviors such as seeking a

warmer or cooler environment.

• It controls energy metabolism by regulating feeding, digestion, and

metabolic rate.

• It regulates reproduction through hormonal control of mating,

pregnancy, and lactation.

• It controls emergency responses to stress, including physical and

immunological responses to stress by regulating blood flow to

muscle and other tissues and the secretion of adrenal stress

hormones.

The hypothalamus serves this integrative function by

regulation of five basic physiological needs:

The Hypothalamus Contains Specialized

Groups of Neurons Clustered in Nuclei

4 g/1400 g adult human brain weight

重點:下視丘各核區參與之生理功能

SON

SCN

AH

PVN

AN

VMH

MPO

LHA

PHA

DMH

重點:下視丘各核區參與之生理功能

Figure 49-11 The structure of the

hypothalamus.

SON

AN VMH

LHADMH

前葉

下視丘

甲狀腺素

The Hypothalamus Controls

the Endocrine System

Guillemin and Schally, 1977 Nobel Prize

內分泌系統簡介

腦下垂體

下視丘

腎上腺

甲狀腺

性腺

Figure 49-12 The hypothalamus controls the pituitary gland both directly

and indirectly through hormone-releasing neurons.

Figure 49-13 The paraventricular nucleus of

the hypothalamus is a microcosm of the

autonomic and endocrine control systems.

PVN

Table 49-2 Hormones of the Posterior Pituitary Gland

Name Structure Function

Vasopressin H-Cys-Tyr-Phe-Gln-Asn-

Cys-Pro-Arg-Gly-NH2 S-S

Vasoconstriction, water

resorption by the kidney

Oxytocin H-Cys-Tyr-Ile-Glu-Asn-

Cys-Pro-Leu-Gly-NH2 S-S

Magnocellular Neurons Secrete

Oxytocin and Vasopressin Directly

From the Posterior Pituitary

後葉

PVN (paraventricular nucleus)

SON (supraoptic nucleus)

Parvocellular Neurons Secrete

Peptides That Regulate Release

of Anterior Pituitary Hormones

Table 49-3 Hypothalamic Substances That Release or Inhibit the Release of Anterior

Pituitary Hormones

Hypothalamic substance Anterior pituitary hormone

Releasing

Thyrotropin-releasing hormone (TRH) Thyrotropin, prolactin

Corticotropin-releasing hormone (CRH) Adrenocorticotropin, β -lipotropin

Gonadotropin-releasing hormone (GnRH) Luteinizing hormone (LH), follicle-stimulating

hormone (FSH)

Growth hormone-releasing hormone

(GHRH or GRH)

Growth hormone (GH)

Prolactin-releasing factor (PRF) Prolactin

Melanocyte-stimulating hormone-

releasing factor (MRF)Melanocyte-stimulating hormone (MSH), β -

endorphin

Inhibiting

Prolactin release-inhibiting hormone

(PIH), dopamine

Growth hormone release-inhibiting

hormone (GIH or GHRIH; somatostatin)

Growth hormone, thyrotropin

Melanocyte-stimulating hormone release-

inhibiting factor (MIF)

Melanocyte-stimulating hormone (MSH)

前葉

前葉

TRH, CRH, GnRH, GRH GIH, PRF PIH, MRF

甲狀腺

前葉

下視丘

前葉

下視丘

性腺

前葉

下視丘

腎上腺皮質素

前葉

Short-term & long-term

nervous system & endocrine system

壓力

內分泌系統

內分泌系統

神經系統

內分泌系統

全自動控溫系統

Homeostasis

set point, receptor, effector

全自動控溫系統

Homeostasis

set point, receptor, effector

Temperature Regulation

Receptor (hypothalamus)

AH/POA

heat sens. cell 2/3

cold sens. cell 1/3

PH

AH

Heat conservation

(shivering)

Heat dissipation

(sweat)

Glucostatic Hypothesis of Appetite

Regulation

• Satiety Center (飽食中樞)-VMH

• Feeding Center (餵食中樞)-LHA

• glucostats: 位於VMH 內，其glucose 利用可控制 VMH 細胞活性

VMH LHA- eat

Relation to Cyclic Phenomena

Infradian (longer than one day)menstral cycle

Circadian (approx. one day)sleeping, body temperature, various hormones, drinking, locomotor activity…

Ultradian (shorter than one day)feeding, respiration, heart rate, nerve impulse discharge

Circadian rhythm: light signal from retina SCN

Circadian Rhythms

Witte et al. 1998, Physiology & Behavior

Sleep-Awake Circuit

1.

2.

Awake Pathway Sleep Pathway

LDT: laterodorsal tegmental nuclei, PPT: pedunculopontine

TMN: tuberomammillary nucleus, Raphe: raphé nuclei, LC: locus coeruleus

VLPO: ventrolateral preoptic nucleus

Sleep center: GABA

S2-S4

T1

L3ACh

75%

8% ACh1.分布較少2.反應較不連續且為局部作用

Hypothalamus:內分泌系統之控制中樞 (PVN, SON, AN, ME...)飽食中樞 (VMH, LHA), 飲水中樞 (CVO, SFO, MPO), 體溫調節中樞 (PH, AH, POA),

sexual behavior, 血壓調控(PVN...), sleep (VLPO)/wake (TMN, LH), circadian rhythms (SCN)

NeuroendocrinologyExternal environment Hypothalamus pituitary gland (Hormones)

Internal condition nervous system (head ganglion of ANS)

Hypothalamus

Anterior pituitary

Posterior pituitary

Homeostasis