Cellular location and major terminal networks of the orexinergic system in the brains of five microchiropteran species.
The present study describes the distribution of Orexin-A immunoreactive cell bodies and terminal networks in the brains of five microchiropteran species. Given the specialized flight and echolocation abilities of the microchiropterans it was of interest to examine if any specific differences in a generally phylogenetically homogenous neural system could be found. The orexinergic neurons have been found within the hypothalamus of all species studied, and were represented by a large cluster that spanned the anterior, dorsomedial, perifornical and lateral hypothalamic regions, with a smaller cluster extending into the region of the medial zona incerta. Evidence for orexinergic neurons in the ventrolateral hypothalamus adjacent to the optic tract was not observed in any microchiropteran species. The terminal networks of the orexinergic neurons conformed to that previously reported in a range of mammalian species, with dense terminal networks being found in the hypothalamus, cholinergic pedunculopontine and laterodorsal tegemental nuclei, the noradrenergic locus coeruleus complex, all serotonergic nuclei, the paraventricular nuclei of the epithalamus and adjacent to the habenular nuclei. Thus, apart from the lack of neurons in the ventrolateral hypothalamus, the orexinergic system of the microchiropterans appears typically mammalian.
Kruger
Jean-Leigh
JL
School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa.
Dell
Leigh-Anne
LA
Pettigrew
John D
JD
Manger
Paul R
PR
D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism; D002685:Chiroptera / Q000033:anatomy & histology* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D000068797:Orexins
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins