Distribution of urocortin‐like immunoreactivity in the central nervous system of the frog Rana esculenta

Abstract

Corticotropin-releasing factor (CRF), sauvagine, and urotensin I are all members of the so-called CRF neuropeptide family. Urocortin (Ucn), a 40-amino-acid neuropeptide recently isolated from the rat brain, is the newest member of this family. Until now, the distribution of Ucn in the central nervous system (CNS) has been studied only in placental mammals. We used a polyclonal antiserum against rat Ucn to determine the distribution of Ucn-like immunoreactivity in the CNS of the green frog, Rana esculenta. The great majority of Ucn-immunoreactive perikarya was seen in the anterior preoptic area, ventromedial thalamic nucleus, posterior tuberculum, nucleus of the medial longitudinal fasciculus, and Edinger-Westphal nucleus. Urocortin-immunoreactive nerve cells were also observed in the motor nuclei of the trigeminal and facial nerves and in the hypoglossal nucleus. Immunoreactive fibers were found in the medial and lateral septal nuclei, bed nucleus of the stria terminalis, many of the thalamic and hypothalamic nuclei, mesencephalic tectum, tegmental nuclei, torus semicircularis, and dorsal horn and central field of the spinal cord. Only scattered Ucn-immunoreactive axon terminals were observed in the external zone of the medial eminence. The densest accumulations of Ucn-immunoreactive nerve terminals were seen in the granular layer of the cerebellum and cochlear nuclei. Our results suggest that an ortholog of mammalian Ucn occurs in the CNS of the green frog. The distribution of Ucn-like immunoreactivity in Rana esculenta showed many similarities to the distribution in placental mammals. The distribution of Ucn-like immunoreactivity in the anuran CNS was different from that of CRF and sauvagine, so our results suggest that at least three different lineages of the CRF neuropeptide family occur in the anuran CNS.

Comparison of the distributions of urocortin‐containing and cholinergic neurons in the perioculomotor midbrain of the cat and macaque

“…As more species have been investigated, however, it has become evident that the location of the preganglionic motor neuron population differs appreciably from species to species and is rarely synonymous with borders of the cytoarchitecturally defined EW (mouse: Van and Atherton, 1991;rabbit: Johnson and Purves, 1981;rat: Smeraski et al, 2004). Instead, numerous centrally projecting peptidergic populations have been found within the EW in cats, rodents, and even frogs, including neurons immunoreactive for CCK, substance P, urocortin, cocaineand amphetamine-regulated transcript (CART), and neuropeptide B (cat: Maciewicz et al, 1983;Phipps et al, 1983; present data; frog: Kozicz et al, 2002;mouse: Bachtell et al, 2002;Tanaka et al, 2003;rat: Innis and Aghajanian, 1986;Kozicz et al, 1998;Hokfelt et al, 2002;Kozicz, 2003;Dun et al, 2005). In fact, it appears that only in those species in which the preganglionic motoneurons are clustered together do they occupy the cytoarchitecturally defined EW, with urocortin ϩ cells located outside its borders (monkey: Vasconcelos et al, 2003;present data;Horn et al, 2007;pigeon: Reiner et al, 1991;Cavani et al, 2003).…”

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

“…In amphibians and mammals, U1 and related peptides (CRF, sauvagine, urocortin) are expressed in the central nervous system (e.g., Refs. 119, 372,772), and this apparently is also true in both teleosts and elasmobranchs (484,766,849). UT-secreting neurons have not been described in fish gills to date.…”

Effect of starvation on Fos and neuropeptide immunoreactivities in the brain and pituitary gland of Xenopus laevis

“…The highly speciWc rabbit anti-Xenopus CRF (xCRF; dilution: 1:15) (Boorse and Denver, 2004;Calle et al, 2005a;Yao et al, 2004), rabbit anti-rat Ucn1 (1:30,000) (Bittencourt et al, 1999;Kozicz et al, 2002), rabbit antibovine ENK (1:1000) (Calle et al, 2005b) and rabbit anti-Xenopus NPY (xNPY; 1:8000) (Tuinhof et al, 1994;Ubink et al, 1997) sera had been used in our laboratories before. The C6-1 F4D4 CART-antiserum (1:100,000) had been raised in mice against the 109-126 fragment of rat CART peptide (Koylu et al, 1997;Lázár et al, 2004).…”