Rise of the Animal Kingdom and Epigenetic Mechanisms of Evolution - Building the Most Complex Structure on Earth - page 286

(A) (B)

Leptinergic/NPYergic
Neurons

Hypothalamus
Hypothalamic-hypophyseal
Circulation

Pituitary

TSH/others

Short
circuits

Sympathetic
nervous system

Thyroid
T 3 /T 4

Arteries

Adrenal
Cortisol

Ovaries
E2

TSHR

TSHR

others

Adrb2

Osteoclast

Peptidergic
receptor
(NPY, CGRP, VIP,
Glu, Sub P)

Osteoblasts

Nerves in bone

Bone matrix

Figure 5.18 Local (A) and global (B) regulation of skeletal homeostasis by the
hypothalamus. Short circuits refer to nonleptinergic, non-NPYergic release of adrenergic
neurotransmitters, as well as epinephrine release from the adrenals. Abbreviations : NPY,
neuropeptide Y; CGRP, calcitonin gene-related peptide; VIP, vasoactive intestinal peptide;
Sub P, substance P; Glu, glutamate; TSH, thyroid-stimulating hormone; TSHR, TSH receptor;
Adrb2 , β2-adrenergic receptor; T 3 and T 4 , thyroid hormones; E2, estradiol.
Source : (slightly simplified) Zaidi (2005) .

Production of the JH by corpora allata in insects is stimulated by the brain hor-
mones allatotropins and inhibited by the JH-inhibiting action of the local nerves
nervi corporis allati I and II (NCA I and II) ( Kou and Chen, 2000; Stay et al., 1996 ).
The global-inhibiting action of brain neurohormones, allatostatins, is counteracted
by the JH-stimulating action of nerves innervating the corpora allata releasing dopa-
mine in these glands ( Granger et al., 1996 ).
The global neural control of male reproductive activity in vertebrates via the
hypothalamic-pituitary-testicular axis is complemented by another neural pathway
from the spinal cord that plays a critical role in the function of Leydig cells in tes-
ticles ( Lee et al., 2002 ). Besides a central hypothalamic pathway, regulation of the
ovarian function is critically involved in the ovarian innervation ( Morales-Ledesma
et al., 2004 ), which only “targets a circumscribed subpopulation of ovarian cells”
( Mayerhof et al., 1997 ).
Many other examples can be presented to demonstrate the existence of an ani-
mal's binary (central and adjacent) neural control of spatial restriction of gene