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Sex‐ and sub region‐dependent modulation of arcuate kisspeptin neurones by vasopressin and vasoactive intestinal peptide
Author(s) -
Schafer Danielle,
Kane Grace,
Colledge William H.,
Piet Richard,
Herbison Allan E.
Publication year - 2018
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/jne.12660
Subject(s) - kisspeptin , medicine , endocrinology , neurokinin b , vasoactive intestinal peptide , neuropeptide , biology , hypothalamus , population , arcuate nucleus , vasopressin , gonadotropin releasing hormone , receptor , hormone , luteinizing hormone , substance p , environmental health
A population of kisspeptin neurones located in the hypothalamic arcuate nucleus ( ARN ) very likely represent the gonadotrophin‐releasing hormone pulse generator responsible for driving pulsatile luteinising hormone secretion in mammals. As such, it has become important to understand the neural inputs that modulate the activity of ARN kisspeptin ( ARN KISS ) neurones. Using a transgenic GC a MP 6 mouse model allowing the intracellular calcium levels ([Ca 2+ ] i ) of individual ARN KISS neurones to be assessed simultaneously, we examined whether the circadian neuropeptides vasoactive intestinal peptide ( VIP ) and arginine vasopressin ( AVP ) modulated the activity of ARN KISS neurones directly. To validate this methodology, we initially evaluated the effects of neurokinin B ( NKB ) on [Ca 2+ ] i in kisspeptin neurones residing within the rostral, middle and caudal ARN subregions of adult male and female mice. All experiments were undertaken in the presence of tetrodotoxin and ionotropic amino acid antagonists. NKB was found to evoke an abrupt increase in [Ca 2+ ] i in 95%‐100% of kisspeptin neurones throughout the ARN of both sexes. By contrast, both VIP and AVP were found to primarily activate kisspeptin neurones located in the caudal ARN of female mice. Although 58% and 59% of caudal ARN kisspeptin neurones responded to AVP and VIP , respectively, in female mice, only 0%‐8% of kisspeptin neurones located in other ARN subregions responded in females and 0%‐12% of cells in any subregion in males ( P < 0.05). These observations demonstrate unexpected sex differences and marked heterogeneity in functional neuropeptide receptor expression amongst ARN KISS neurones organised on a rostro‐caudal basis. The functional significance of this unexpected influence of VIP and AVP on ARN KISS neurones remains to be established.