The Adrenal Glands PartⅠThe Adrenal medulla

Ziying WANGInstitute of Pharmacology School of Medicine, Shandong Universitywangziying@sdu.edu.cn

Part 1 Introduction

Adrenal Glands

Blood supply

Nerve supply

AD

Embryology of the adrenal gland

Part 2 Adrenal medullaAt the interface between the neural

and endocrine system

Case: Mrs. Smith, a 45-year-old woman

• Worried for panic attacks– Sweating – Palpitation– Sudden episodes of rapid heart beating– Frightened

• Examination– Pale– P: 100/min– BP: 155/105 to 260-165 mmHg

• Investigation– Serum sodium: 141mmol/L (→)– Serum potassium : 3.2mmol/L (↓)– Plasma noradrenaline: 12nmol/L (↑ ↑)– Plasma adrenaline: 6.7nmol/L (↑ ↑ ↑ ↑)

Adrenal medulla

• Composed of polygonal cells arranged in cords or cluster

• Numerous wide diameter capillaries

• Sympathetic ganglion

Adrenal medulla chromate salt stain

– Brownish cytoplasm granules- when fixed by chromate salt containing fixative

– Also called chromaffin cell

Hormones of adrenal medulla

Catecholamines

Adrenaline

Noradrenaline

Dopamine

Peptides

Opiate peptides

Adrenomedullin

Arginine vasopressin

Vasoactive intestinal peptide

Catecholamine (CA)

Synthesis of catecholamine

Synthesis of catecholamine

• PNMT• Regulated by glucocorticoids.

Secretion of catecholamine

Regulation of catecholamine secretion

• The activity of the adrenal medulla is regulated by the activity of the sympathetic nerve.

Transport and metabolism of adrenal medullary hormones

(1) No specific binding proteins

(2) Onset rapid and short-lived

(3) Metabolized by COMT and MAO

(4) End product: VMA

Actions of adrenal medullary hormones

• Fight and flight neuroendocrine response

• Emergency reaction hypothesis:

W. B. Cannon, 1928

• Through activating adrenoceptors

Case: What is the cause?

Over-secretion of the CA

– Palpitation– Sudden episodes of rapid heart beating– Frightened– Pale– P: 100/min– BP: 155/105 to 260-165 mmHg– Plasma noradrenaline: 12nmol/L (↑ ↑)– Plasma adrenaline: 6.7nmol/L (↑ ↑ ↑ ↑)

Part 3 Disorders of the adrenal medulla

Phaeochromocytoma: a tumor causes

adrenal medullary hormones over-secretion

Phaeochromocytoma

Symptoms: with emergency reaction frequently

Diagnosis

(1) CT and MIBG: localization

(2) Symptoms: HBP, HG, high BMR

(3) VMA, AD and NA in urine

Treatment

(1) Operation

(2) Adrenoceptor antagonists• α-adrenoreceptor blockers• β-adrenoreceptor blockers

Case: treatment

(1) Drug treatment:α-blockers→β- blockers

(2) To find the source: CT and MIBG scan

(3) Operation

Familial Phaeochromocytoma

Part 3 Pharmacological uses of adrenal medullary hormones

Clinical uses of adrenaline

1. Cardiac arrest

2. Allergic shock: first choice

3. Bronchial asthma

4.Prolongation of local anesthetic duration

5. Topical hemorrhage

bronchial mucosa vessel dilation

↑HA, SRS, PGs, BK

Ag-Ab

Allergized cells

Bronchial SM contraction

dyspnea

Intrathoracic pressure↑

↓returned blood volume

↓SBP

Vessel dilation

DBP↓

mucosal edema

AD: first choice for allergic shock

AD

x

x xx

x

Clinical uses of NA

1. Shock and hypotension

2. Upper digestive tract hemorrhage

Endocrine hypertension

Belongs to secondary hypertension:

Conn’s syndrome

Cushing’s syndrome

Phaeochromocytoma