Immunohistochemical Localization of Substance P And Cholecystokinin in the Dorsal Root Ganglia and Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)

Abstract

The presence of substance P (SP) and cholecystokinin (CCK) immunoreactive neurons was examined in the bottlenose dolphin dorsal root ganglia (DRGs) and spinal cord by immunohistochemical techniques. SPpositive and CCK-immunoreactive neurons were respectively $50% and 1% of the total number of ganglion cells examined and especially belonged to small and medium-sized cell populations. Using double labeling techniques we observed that SP-and CCK-immunoreactivity coexisted in a very low number of primary afferent neurons (2.7%). Few SPimmunoreactive (IR) neurons (2.7%) were also CCK-positive. On the contrary, 65% of CCK-immunoreactive neurons contained SP. Interestingly, we observed CCK-immunoreactive satellite glial cells located around large cell class somata. Virtually no SP-IR and CCK-positive neurons were surrounded by peripheral CCK-immunoreactive satellite glial cells. The SP-IR and CCK-positive nerve fibers were particularly conspicuous in the superficial layers of the spinal cord. The present study indicates that SP and CCK only partially overlap in the thoracic, lumbar, and caudal DRGs of the bottlenose dolphin, suggesting that the majority of SP-IR ganglion neurons are lacking in CCK-immunoreactivity. The role of SPcontaining DRG neurons is discussed also in relation to the huge vascular spinal retia mirabilia typical of cetaceans. Anat Rec, 293:477-484, 2010. V V C 2010 Wiley-Liss, Inc.

Nitrergic Neurons in the Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)

“…Moreover, NO, located in sympathetic nerves, can be released as a co-transmitter in the peripheral autonomic system and induces vasodilator effects (Toda and Okamura, 2003). It is well known that Cetaceans have morphophysiological features that permit them to live in aquatic environment (Nagel et al, 1968;Vogl and Fisher, 1981;Ochrymowych and Lambertsen, 1984;Melnikov, 1997;Bombardi et al, 2010Bombardi et al, , 2011. In particular, during diving, blood is shifted to the huge retia mirabilia, to allow physiological distribution of fluids, permit thoracic compression at depth, heat the spinal cord, and regulate the oxygenation of the brain during the long breath-holding dives.…”

Neurochemical features of boar lumbosacral dorsal root ganglion neurons and characterization of sensory neurons innervating the urinary bladder trigone

“…The expression of CGRP, SP, and nNOS immunoreactivity in DRG varies widely among species and also at different DRG levels within the same species (Kai‐Kai,1989; Lawson,1995; Kashiba et al,1999; Zwick et al,2002; Weissner et al,2006; Price and Flores,2007; Tan et al,2008; Bombardi et al,2010; Russo et al,2010a, 2011a).…”

Distribution of Nitrergic Neurons in the Dorsal Root Ganglia of the Bottlenose Dolphin (Tursiops truncatus)

“…Thereafter, the sections were incubated for 48 hr at 4 C with a specific primary antibodies solution described in the following. As the neurofilament 200 kDa is virtually expressed by every DRG neuron of the bottlenose dolphin (Bombardi et al, 2010), we used this protein as pan-neuronal marker to determine the percentage of nNOS-IR neurons. In particular, we colocalized mouse monoclonal antibody anti-nNOS (1:100; sc-5302; Santa Cruz Biotechnology, CA) with rabbit polyclonal antibody anti-NF 200 kDa (1:2,000; N4142; Sigma, Saint Louis, MO).…”

“…As in other species, smalland medium-sized neurons of the DRGs of the bottlenose dolphin can express substance P (SP). However, SP-immunoreactive (IR) neurons are more represented in bottlenose dolphin DRGs ($50% of the total primary afferent neurons) than in others mammals (Lawson, 1992;Willis and Coggeshall, 2004;Bombardi et al, 2010). This data suggest that in the cetaceans SP-IR DRGs neurons could be involved not only in the transmission of nociceptive information but also in the direct regulation of the blood circulation, acting on the vascular tone (Bombardi et al, 2010).…”