Mapping of Neurotensin in the Alpaca (Lama pacos) Brainstem

Abstract

We studied the distribution of cell bodies and fibres containing neurotensin (NT) in the brainstem of the alpaca using an indirect immunoperoxidase technique. Immunoreactive fibres were widely distributed throughout the brainstem, whereas the distribution of cell bodies was less widespread. Immunoreactive perikarya were only found in the mesencephalic and bulbar reticular formation, periaqueductal grey, nucleus of the solitary tract, laminar spinal trigeminal nucleus and in the inferior colliculus. A high density of fibres containing NT was found in the dorsal nucleus of the raphe, marginal nucleus of the brachium conjunctivum, locus coeruleus, inferior colliculus, inter-peduncular nucleus, substantia nigra, periaqueductal grey, reticular formation of the mesencephalon, pons and medulla oblongata, nucleus of the solitary tract, laminar spinal trigeminal nucleus, hypoglossal nucleus, inferior central nucleus and in the tegmental reticular nucleus. The widespread distribution indicates that NT might be involved in multiple physiological actions in the alpaca brainstem; this must be investigated in the future as alpacas lives from 0 m above sea level to altitudes of up 5000 m and hence the involvement of this neuropeptide in special and unique regulatory physiological mechanisms could be suggested.

Mapping of tyrosine hydroxylase in the alpaca (Lama pacos) brainstem and colocalization with CGRP

“…For the nomenclature and location of the catecholaminergic groups in the brainstem, we used the already published maps of the alpaca brainstem (de Souza et al, 2007Souza et al, , 2008, as well as the descriptions of Dahlströ m and Fuxe (1964), while those of Hö kfelt et al (1984) were used as the main references. The distribution of the catecholaminergic cell groups in the brainstem of other mammalian species was also checked (Badlangana et al, 2007a;Bhagwandin et al, 2008;Bux et al, 2010;Da Silva et al, 2006;Dell et al, 2010;Dwarika et al, 2008;Gravett et al, 2009;Kruger et al, 2010;Limacher et al, 2008;Manger et al, 2002Manger et al, , 2003Manger et al, , 2004Moon et al, 2007;Pieters et al, 2010;Smeets and Gonzá lez, 2000;Tillet and Kitahama, 1998;Tillet and Thibault, 1989).…”

“…This species is very important in the economy of some South American countries like Peru thanks to its excellent quality wool (de Souza et al, 2007). For this reason, those studies previously carried out on alpacas have mainly covered reproductive aspects; for example, hormonal mechanisms (see de Souza et al, 2008 for a review).…”

“…Recently, the distributions of leucine-enkephalin (Leu-enk) and calcitonin gene-related peptide (CGRP) in the alpaca brainstem have been published (de Souza et al, 2007(de Souza et al, , 2008. These two neuropeptides are implicated in multiple functions (see Marcos, 2007) and their distributions in the alpaca brainstem (particularly CGRP) suggest they can play some role, among others, in cardiovascular regulation (see Díaz-Cabiale et al, 2007).…”

Mapping of CGRP in the alpaca diencephalon

“…In South America camelid research has been focused in general on their reproductive mechanisms (Bravo et al, 1996;Correa et al, 1997;Ratto et al, 1997Ratto et al, , 2005Ratto et al, , 2006 due to the economic importance of their wool, although recently the distribution of three neuropeptides belonging to different families of peptides (leucine-enkephalin, calcitonin gene-related peptide (CGRP), somatostatin-28 (1-12)) and tyrosine hydroxylase has been reported in the alpaca central nervous system (brainstem and diencephalon) (de Souza et al, 2007(de Souza et al, , 2008Coveñ as et al, 2011;Marcos et al, 2011). In this sense, the distribution of CGRP has been reported in the alpaca brainstem (de Souza et al, 2008) and the colocalization of this neuropeptide with tyrosine hydroxylase has been also studied in the same central nervous system region of this ungulate (Marcos et al, 2011).…”

Mapping of somatostatin-28 (1–12) in the alpaca diencephalon

“…No study has been carried out using immunocytochemical techniques on the distribution of neuropeptides in the central nervous system of camelids, except for two recent studies carried out on the distribution of immunoreactive fibers and cell bodies containing leucineenkephalin or calcitonin gene-related peptide in the alpaca brainstem (de Souza et al, 2007(de Souza et al, , 2008 and another focused on the colocalization of calcitonin gene-related peptide and tyrosine hydroxylase in the alpaca brainstem (Marcos et al, 2011). In this sense, no study addressing the presence of somatostatin-immunoreactive structures in the alpaca diencephalon has been reported.…”