-
a1-ADRENORECEPTORS FOUND IN:
- POSTJUNCTIONAL SITES:
- EFFECTOR ORGANS, TISSUES AND GLANDS INNERVATED BY SYMP NERVES
INC INTRACELLULAR INH OF ADEN CYCL --> DEC cAMP
SIGNAL BY IP3 & DAG
-
a2 - ADRENORECEPTORS FOUND AT
- 1. POSTJUNCTIONAL SITES:
- EFFECTOR ORGANS, TISSUES AND GLANDS INNERVATED BY SYMP NERVES
INC INTRACELLULAR INH OF ADEN CYCL --> DEC cAMPIP3 & DAG
- 2. PREJUCTIONAL SITES:
- SYMP NEURONS (AUTO --> Gi INC K)
PARASYMP NEURONS OF SA, SPHINC OF IRIS, GI, (HETERO --> Gi INC K)
-
b1-ADRENORECEPTORS FOUND AT
- POSTJUNCIONAL SITES:
- CARDIAC MUSCLES
CARDIAC CONDUCTION TISSUE
ADIPOCYTES
JG CELLS OF RENAL AFFERENT ARTERIOL
-
b2-ADRENORECEPTORS FOUND AT
- POSTJUNTIONAL SITES:
- ARTERIOLS AND VENULES
BRONCHIOLS
UTERUS
GI
LIVER
- PREJUNCTIONAL SITES:
- SYMP NEURONS (HETERO)
-
SYMP MUSCLES OF EYE
RADIAL, IRIS -- a1
SMOOTH MUSC OF EYELID --a?
CANAL OF SCHLEMM -- NOT INERVATED BUT:
- a1 -- ENHANCED OUTFLOW
- a2 -- DEC PROD
-
DISTRIBUTION OF a AND b2 IN ARTERIOL BEDS
b2 PREDOMINATE IN SKEL MUSC
a PREDOMINATE IN GI AND KIDNEY
-
EPI, NE, AND PE SELECTIVITY
- EPI -- b2 > b1 > a
- NE -- a > b1 > b2
- PE -- a1 ONLY
PE = PHENYLEPHRINE
-
a1 RECEPTOR: LOCATIONS AND ACTION
- Eye
- enhanced normal
- outflow of canal of schlemm
- Eye
- radial muscle
- contraction of iris (dilation, mydriasis)
- Kidney
- proximal tubule
- increased sodium/water reabsorption
- Lung
- bronchial gland
- secretion decrease
- Salivary Glands
- water and K+ secretion (viscous and sticky)
- Skin
- pilomotor muscle
- contraction
- --a1a--
- Male Sex Organs
- vas deferens, ampulla, prostate gland and seminal vesicles emission and ejaculation
- Urinary Tract
- trigone and ext. sphincter
- contraction
-
a2 RECEPTOR: LOCATIONS AND ACTION
- Eye
- decreased production of aq fluid in eye
- Pancreas
- islet (B) cells
- (insulin) decreased secretion
- Stomach and Intestines
- motility and tone decreased
- Stomach and Intestines
- secretion is inhibited
-
b2 RECEPTOR: LOCATIONS AND ACTION
- Arterioles
- dilation (via circulating Epi)
- Gallbladder and ducts
- relaxation
- Liver
- glycogenolysis and gluconeogenesis increase
- Lung
- bronchial muscle
- relaxation
- Skeletal Muscle
- glycogenolysis, K+ uptake, tremor, and increased contractility
- Uterus
- relaxation for pregnant and nonpregnant women
- Venules
- dilation (via circulating Epi)
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