Immunohistochemical distribution and biological activity of pituitary adenylate cyclase‐activating polypeptide (PACAP) in the central nervous system of the frog Rana ridibunda

Abstract

The primary structure of frog pituitary adenylate cyclase-activating polypeptide (PACAP) has recently been determined and the results show that the sequence of PACAP has been highly conserved during evolution. In particular, the structure of the 1-27 fragment of PACAP is identical in frog and mammals. Using an antiserum raised against PACAP27, we have investigated the distribution of PACAP-containing neurons in the central nervous system of the frog Rana ridibunda by the immunofluorescence technique. The main populations of immunoreactive perikarya were located in the medial and ventral diencephalon, i.e., the preoptic nucleus, the ventral and dorsal infundibular nuclei, the nucleus posterocentralis thalami, and the ventral and ventrolateral areas of the thalamus. In the telencephalon, sparse cell bodies were found in the nucleus accumbens septi, the amygdala, the pallial commissure, and the bed nucleus of the pallial commissure. In the hindbrain, the torus semicircularis, the nucleus profundus and the nucleus anteroventralis tegmenti of the mesencephalon also contained populations of PACAP-immunoreactive perikarya. Beaded nerve fibers were observed throughout the brain. Occasionally they formed bundles, e.g., from the ventral infundibulum to the external vascular layer of the median eminence, from the central thalamus to the optic tectum, and rostrocaudally, from the nucleus accumbens septi to the nucleus entopeduncularis. Other areas, such as the interpeduncular nucleus, the nucleus isthmi and the roots of cranial nerves V and VIII in the medulla oblongata, were also densely innervated. The adenylate cyclase-stimulating activity of PACAP was tested by using a static incubation technique for hypothalamic slices.(ABSTRACT TRUNCATED AT 250 WORDS)

Pituitary Adenylate Cyclase-Activating Polypeptide and Its Receptors: 20 Years after the Discovery

“…The location of PACAP-containing neurons has also been investigated in the CNS of nonmammalian vertebrates including birds (Peeters et al, 1998;Nowak and Zawilska, 2003), amphibians (Yon et al, 1992(Yon et al, , 1993b) and fishes (Matsuda et al, 1997(Matsuda et al, , 2005bMontero et al, 1998;Jakab et al, 2004;Mathieu et al, 2004). Overall, the distribution of PACAP-immunoreactive cells exhibits a high degree of similarity with that of mammals.…”

“…Soon after the characterization of PACAP, the distribution of the peptide has been investigated in the brain of mammals Köves et al, 1991;Vigh et al, 1991;Kivipelto et al, 1992;Ghatei et al, 1993) and amphibians (Yon et al, 1992). In rat, radioimmunoassay measurements have revealed that the highest concentrations of PACAP occur in the hypothalamic area Ghatei et al, 1993).…”

“…part ϩϩ ϩ ϩϩ Köves et al, 1991Köves et al, , 1994bSkoglösa et al, 1999c Hypothalamus Anterior commissure -ϩϩ Köves et al, 1991Köves et al, , 1994aHannibal, 2002 Anterior commissural nucleus ϩϩ - Köves et al, 1991Köves et al, , 1994a,b Anterior hypothalamic area -/ϩ -/ϩϩ Köves et al, 1994a,b;Piggins et al, 1996;Hannibal, 2002 Arcuate nucleus ϩϩ -/ϩϩ -/ϩϩ Kivipelto et al, 1992;Köves et al, 1994a,b;Murase et al, 1995;Piggins et al, 1996;Das et al, 2007 Köves et al, 1991Köves et al, , 1994aKivipelto et al, 1992;Kimura et al, 1994;Tamada et al, 1994;Hannibal et al, 1995b;Mikkelsen et al, 1995Median eminence, external zone -ϩϩ Köves et al, 1991, 1994aKivipelto et al, 1992;Kimura et al, 1994;Tamada et al, 1994;Hannibal et al, 1995a;Hannibal et al, 1995b;Mikkelsen et al, 1995;Piggins et al, 1996 290 anterior preoptic area, the ventral magnocellular preoptic nucleus, the suprachiasmatic nucleus (SCN), the ventral hypothalamic nucleus, and the posterior tubercle (Yon et al, 1992]. Likewise, in the primitive teleost fish Anguilla anguilla, PACAP-containing neurons are primarily located in the parvo-and magnocellular subdivisions of the preoptic nucleus (Montero et al, 1998).…”

Immunohistochemical localization and biochemical characterization of hypocretin/orexin-related peptides in the central nervous system of the frogRana ridibunda

“…All these hypothalamic nuclei contain neuroendocrine neurons that project to the median eminence and the neurointermediate lobe of the pituitary (Neary and Northcutt 1983;Tuinhof et al, 1994). In frog, some of these neurons express various hypophysiotropic neuropeptides such as corticotropin-releasing factor , thyrotropin-releasing hormone (Lamacz et al, 1989), somatostatin (Laquerrière et al, 1989), growth hormonereleasing hormone (Marivoët et al, 1988), gonadotropinreleasing hormone (Andersen et al, 1988;Collin et al, 1995), pituitary adenylate cyclase-activating polypeptide (Yon et al, 1992), ␣-melanocyte-stimulating hormone (Benyamina et al, 1986), melanin-concentrating hormone (Andersen et al, 1986), neuropeptide Y (Danger et al, 1985), enkephalins (Merchenthaler et al, 1989), calcitonin gene-related peptide (Mulatero and Fasolo, 1991), and galanin (Lázá r et al, 1991). That hcrt-immunoreactive fibers were not detected in the frog median eminence suggests that hcrts do not directly regulate the activity of adenohypophysial cells.…”

Identification of a cDNA encoding a novel amphibian growth hormone-releasing peptide and localization of its transcript

“…It may be that the expression level of fGRP mRNA in the POA and MSA was too low to detect the signal in these brain regions with the present in situ hybridization or that some other undiscovered peptide(s) that cross-reacts with the antiserum against fGRP exists in the POA and MSA. Notwithstanding such discrepancy in the POA and MSA, many neuropeptides, such as thyrotropin-releasing hormone, galanin, PACAP, and somatostatin are known to be expressed in the SCN of the frog (Lamacz et al 1989, Laquerrière et al 1989, Lázár et al 1991, Yon et al 1992. We need to elucidate the co-localization of fGRP/fGRPRPs and these neuropeptides and their interaction in the frog SCN.…”