The Sensory Circumventricular Organs of the Mammalian Brain

by McKinley, Michael J.; McAllen, Robin M.; Davern, Pamela J.; Giles, Michelle E.; Penschow, J.; Sunn, N.

• ISBN13: 9783540004196
• ISBN10: 354000419X
• Format: Paperback
• Copyright: 2003-08-01
• Publisher: Springer Nature

Summary

The brain's three sensory circumventricular organs, the subfornical organ, organum vasculosum of the lamina terminalis and the area postrema lack a blood brain barrier and are the only regions in the brain in which neurons are exposed to the chemical environment of the systemic circulation. Therefore they are ideally placed to monitor the changes in osmotic, ionic and hormonal composition of the blood. Book jacket.

Table of Contents

1 Introduction	1	(2)
2 Location, General Structure and Ependymal Cells of Sensory Circumventricular Organs	3	(14)
2.1 Subfornical Organ	3	(4)
2.1.1 Location	3	(4)
2.1.2 Ependymal Surface of the Subfornical Organ	7	(1)
2.2 OVLT	7	(8)
2.2.1 Location and Structure	7	(7)
2.2.2 Ependymal Surface of the OVLT	14	(1)
2.3 Area Postrema	15	(2)
2.3.1 Location and Structure	15	(1)
2.3.2 Ependymal Surface of the Area Postrema	16	(1)
3 Regional Subdivisions Within Sensory Circumventricular Organs	17	(6)
3.1 Subfornical Organ	17	(2)
3.2 OVLT	19	(2)
3.3 Area Postrema	21	(2)
4 Vasculature, Compartmental Barriers, Neurons and Glia in the Sensory Circumventricular Organs	23	(12)
4.1 Subfornical Organ	23	(5)
4.1.1 Arterial Sources and Venous Drainage	23	(1)
4.1.2 Capillary Plexus	23	(3)
4.1.3 Compartmental Barriers	26	(2)
4.1.4 Neurons and Glia	28	(1)
4.2 OVLT	28	(4)
4.2.1 Arterial Sources	28	(2)
4.2.2 Capillary Plexus and Venous Drainage	30	(1)
4.2.3 Compartmental Barriers	30	(1)
4.2.4 Neurons and Glia	30	(2)
4.3 Area Postrema	32	(3)
4.3.1 Arterial Sources and Venous Drainage	32	(1)
4.3.2 Capillary Plexus	32	(1)
4.3.3 Compartmental Barriers	33	(1)
4.3.4 Neurons and Glia	33	(2)
5 Neurochemical Aspects of Sensory Circumventricular Organs	35	(20)
5.1 Receptors	35	(12)
5.1.1 Acetylcholine	35	(1)
5.1.2 Angiotensin	36	(3)
5.1.3 Bradykinin	39	(1)
5.1.4 Calcium	39	(1)
5.1.5 Calcitonin, Calcitonin Gene-Related Peptide Amylin and Adrenomedullin	39	(2)
5.1.6 Cholecystokinin	41	(1)
5.1.7 Endothelin	41	(1)
5.1.8 Galanin	42	(1)
5.1.9 γ-Aminobutyric acid	42	(1)
5.1.10 Glucagon-Like Peptide-1 Amide	42	(1)
5.1.11 Glutamate	43	(1)
5.1.12 Imidazoline Receptors	43	(1)
5.1.13 Lipopolysaccharide	43	(1)
5.1.14 Natriuretic Peptides (ANP, BNP and CNP)	44	(1)
5.1.15 Neurokinin Receptors	44	(1)
5.1.16 Neurotensin	44	(1)
5.1.17 Neuropeptide Y, Peptide YY, Pancreatic Polypeptide	45	(1)
5.1.18 Prostaglandins	45	(1)
5.1.19 Purinergic Receptors	45	(1)
5.1.20 Relaxin	45	(1)
5.1.21 Serotonin	46	(1)
5.1.22 Somatostatin	46	(1)
5.1.23 Steroid Receptors	46	(1)
5.1.24 Vasopressin and Oxytocin Receptors	47	(1)
5.2 Neurotransmitters, Neuropeptides, Hormones and Enzymes	47	(8)
5.2.1 Acetylcholine	47	(1)
5.2.2 Angiotensin II, Angiotensin III and Angiotensinogen	47	(1)
5.2.3 Angiotensin-Converting Enzyme	48	(1)
5.2.4 Catecholamines	48	(1)
5.2.5 Cholecystokinin	49	(1)
5.2.6 Enkephalin	49	(1)
5.2.7 Glutamate, GABA and Glycine	49	(1)
5.2.8 Luteinising Hormone-Releasing Hormone	50	(1)
5.2.9 Neurotensin	50	(1)
5.2.10 Nitric Oxide Synthase	50	(2)
5.2.11 Orexins	52	(1)
5.2.12 Proopiomelanocortin Peptides and Enkephalin	52	(1)
5.2.13 Serotonin	52	(2)
5.2.14 Vasopressin	54	(1)
6 The Neural Connections of the Sensory Circumventricular Organs	55	(12)
6.1 Subfornical Organ	55	(6)
6.1.1 Efferent Neural Connections	55	(4)
6.1.1.1 Viral Tracing	59	(1)
6.1.2 Afferent Neural Pathways of the Subfornical Organ	59	(2)
6.2 Neural Connections of the OVLT	61	(3)
6.2.1 Efferent Projections	61	(2)
6.2.1.1 Polysynaptic Efferent Pathways to the Periphery	62	(1)
6.2.2 Afferent Projections	63	(1)
6.3 Area Postrema	64	(3)
6.3.1 Efferent Neural Connections	64	(2)
6.3.2 Afferent Projections	66	(1)
7 Immediate-Early Gene Expression in Sensory Circumventricular Organs	67	(14)
7.1 Angiotensin II	67	(5)
7.1.1 Intravenous Infusion of Angiotensin II	67	(1)
7.1.2 Intracerebroventricular Angiotensin II	68	(1)
7.1.3 Endogenous Angiotensin II	69	(5)
7.1.3.1 Sodium Depletion	69	(2)
7.1.3.2 Haemorrhage	71	(1)
7.1.3.3 Isoproterenol	71	(1)
7.1.3.4 Locally Generated Angiotensin II in the CVOs	71	(1)
7.2 Baroreceptor Activation	72	(1)
7.3 Carbachol	73	(1)
7.4 Anorectic Peptides - Cholecystokinin, GLP-1 and Amylin	73	(1)
7.5 Hypertonicity	74	(3)
7.5.1 Intravenous Infusion of Hypertonic Solutions	74	(2)
7.5.2 Dehydration	76	(1)
7.6 Lipopolysaccharide (Endotoxin)	77	(1)
7.7 Relaxin	78	(1)
7.8 Vomiting and Emetic Stimuli	78	(3)
8 Functions of the Sensory Circumventricular Organs	81	(18)
8.1 Osmoregulation	81	(6)
8.1.1 Sites of Cerebral Osmoreceptors	82	(3)
8.1.2 Osmoregulation of Natriuresis and Renin Secretion	85	(1)
8.1.3 Influences of Relaxin on Osmoregulation	86	(1)
8.2 Central Actions of Circulating Angiotensin	87	(3)
8.2.1 Water Drinking	87	(1)
8.2.2 Angiotensin-Induced Vasopressin Secretion	88	(1)
8.2.3 Sodium Hunger	89	(1)
8.3 Influences on Arterial Pressure	90	(4)
8.3.1 Area Postrema	90	(2)
8.3.2 OVLT	92	(1)
8.3.3 Subfornical Organ	93	(1)
8.3.4 The Extended Autonomic Neuraxis	93	(1)
8.4 Area Postrema and Vomiting	94	(1)
8.5 Neuroimmune Responses and Fever	95	(2)
8.6 Concluding Remarks	97	(2)
References	99	(24)
Subject Index	123