Neural systems mediating seasonal breeding in the ewe.
Seasonal reproduction in ewes is caused by a dramatic increase in response to oestradiol (E(2)) negative feedback during the nonbreeding (anoestrous) season. Considerable evidence supports the hypothesis that A15 dopaminergic neurones in the retrochiasmatic area (RCh) play a key role in these seasonal changes. These A15 neurones are stimulated by E(2) and inhibit gonadotrophin-releasing hormone (GnRH) secretion in anoestrus, but not the breeding season. Because A15 neurones do not contain oestrogen receptors-alpha (ER alpha), it is likely that E(2)-responsive afferents stimulate their activity when circulating E(2) levels increase during anoestrus. Retrograde tract tracing studies identified a limited set of ER alpha-containing afferents primarily found in four areas [ventromedial preoptic area, RCh, ventromedial and arcuate (ARC) nuclei]. Pharmacological and anatomical data are consistent with GABA- and glutamate-containing afferents controlling A15 activity in anoestrus, with E(2) inhibiting GABA and stimulating glutamate release at this time of year. Tract tracing demonstrated that A15 efferents project posteriorly to the median eminence and the ARC, suggesting possible direct actions on GnRH terminals or indirect actions via kisspeptin neurones in the ARC to inhibit GnRH in anoestrus. Identification of this neural circuitry sets the stage for the development of specific hypotheses for morphological or transmitter/receptor expression changes that would account for seasonal breeding in ewes.
Goodman
R L
RL
Department of Physiology & Pharmacology, West Virginia University, Morgantown, WV, USA. bgoodman@hsc.wvu.edu
Jansen
H T
HT
Billings
H J
HJ
Coolen
L M
LM
Lehman
M N
MN
D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D001947:Breeding; D004298:Dopamine / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D005260:Female; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D012756:Sheep / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D004958:Estradiol; D005680:gamma-Aminobutyric Acid; D004298:Dopamine
Endocrinology. 2000 Nov;141(11):4218-25
11089556
Endocrinology. 1977 Sep;101(3):818-24
560960
Biol Reprod. 1982 Oct;27(3):580-9
6753958
Endocrinology. 1980 Nov;107(5):1286-90
7000489
Endocrinology. 1989 Mar;124(3):1579-81
2563684
Biol Reprod. 2000 Nov;63(5):1352-7
11058538
Endocrinology. 2008 Jun;149(6):2762-72
18325998
J Neuroendocrinol. 1998 Jul;10(7):551-8
9700682
Endocrinology. 2010 Aug;151(8):3836-46
20519368
Endocrinology. 2003 Aug;144(8):3663-76
12865349
Histochemistry. 1990;93(3):327-33
2312361
Biol Reprod. 2002 Sep;67(3):829-36
12193391
J Endocrinol. 2005 Aug;186(2):397-409
16079265
Endocrinology. 1994 Apr;134(4):1905-14
7907976
J Chem Neuroanat. 2000 May;19(1):47-67
10882837
J Neurosci Methods. 1999 Sep 15;91(1-2):1-8
10522819
Neurosci Lett. 2006 Jul 3;401(3):225-30
16621281
Mol Cell Endocrinol. 2006 Jun 27;252(1-2):69-73
16647195
J Neuroendocrinol. 2008 Jun;20(6):732-42
18601696
Biol Reprod. 2003 Mar;68(3):846-52
12604634
Endocrinology. 1999 Dec;140(12):5929-36
10579360
Physiologist. 1980 Dec;23(6):29-38
7208642
Biol Reprod. 1997 Jun;56(6):1544-9
9166708
Neuroendocrinology. 1989 Jan;49(1):80-7
2497396
Cell Tissue Res. 1995 Sep;281(3):561-7
7553775
Biol Reprod. 1992 Jun;46(6):1130-5
1391310
Biol Reprod. 1991 Mar;44(3):476-82
1673066
Endocrinology. 1996 Oct;137(10):4443-50
8828506
J Neuroendocrinol. 1991 Aug 1;3(4):387-91
19215481
Biol Reprod. 1994 May;50(5):1168-77
7912958
Recent Prog Horm Res. 1984;40:185-232
6385166
J Comp Neurol. 2003 Oct 6;465(1):136-44
12926021
Endocrinology. 2004 Jun;145(6):2959-67
14988383
Mol Endocrinol. 2003 Jun;17(6):1039-53
12624116
Reprod Sci. 2007 Feb;14(2):101-16
17636222
Endocrinology. 2006 Oct;147(10):4843-51
16857749
Endocrinology. 1998 Apr;139(4):1508-16
9528928
Neuroendocrinology. 1993 Apr;57(4):751-9
8367037
Endocrinology. 1994 Apr;134(4):1806-11
8137746
Biol Reprod. 1986 Oct;35(3):562-71
2878692
Endocrinology. 1997 Jun;138(6):2585-95
9165052
J Reprod Fertil Suppl. 1995;49:285-96
7623320
Endocrinology. 1985 May;116(5):2054-61
2859194
J Endocrinol. 1983 Feb;96(2):181-93
6827203
Endocrinology. 2008 Nov;149(11):5770-82
18617612
Biol Reprod. 1985 May;32(4):779-87
4005347
Reprod Suppl. 2002;59:149-65
12698979
Biol Reprod. 1984 Mar;30(2):374-81
6538445
Endocrinology. 2000 Jan;141(1):190-6
10614639
Endocrinology. 2004 Sep;145(9):4264-7
15178649
Biol Reprod. 1994 Apr;50(4):965-76
8199277
Endocrinology. 1993 Aug;133(2):887-95
8102098
Endocrinology. 2009 Oct;150(10):4663-71
19589862
Endocrinology. 2007 Dec;148(12):5752-60
17823266
Biol Reprod. 1997 Mar;56(3):655-62
9047010
J Neuroendocrinol. 2001 Dec;13(12):1051-8
11722701