NADPH-diaphorase activity in the nociceptive pathways of land snail Megalobulimus abbreviatus: the involvement of pedal ganglia

Abstract

NADPH-diaphorase (NADPH-d) is a histochemical marker for nitric oxide synthase (NOS), widely used to identify nitric oxide (NO) producing cells in the nervous system of both vertebrates and invertebrates. Using NADPH-d histochemistry and semi-quantitative optical densitometry, we characterized the NO-producing neurons in the pedal ganglia of young and adult Megalobulimus abbreviatus, subjected to aversive thermal stimulus. The animals were killed at different times (3, 6, 12 and 24 h) following stimulus. The enzymatic activity was detected in different cellular subsets and neuronal processes. In all the studied pedal ganglia subregions, the optical density of positive neurons (P < 0.05) and neuropilar area 1 (P < 0.01) was significantly different in treated animals when compared to controls. The increase in nitrergic activity induced by nociceptive stimulus suggests the involvement of NO in the nociceptive circuit of M. abbreviatus, which is well maintained throughout evolution, and could be helpful in drawing cellular homologies with other gastropods.

Changes in the nitric oxide system in the shore crab Hemigrapsus sanguineus (Crustacea, decapoda) CNS induced by a nociceptive stimulus

“…The injury-related increase of NADPH-d and iNOS activity in the crab CNS is consistent with data obtained on insects and mollusks (Rigon et al, 2009). Thermal nociceptive stimulation enhances NOS activity in peripheral sensory neurons, nerve cells of the thoracic ganglion, and mushroom bodies of Drosophila (Xu et al, 2006).…”

“…However, little is known about the action of nitric oxide in local circuits that process nociceptive signals in invertebrates. Changes in NO production induced by exogenous noxious stimulation were recorded in neurons of Aplysia (Sung et al, 2004), H. medicinalis (Yahyavi-Firouz-Abadi et al, 2007) and Megalobulimus abbreviates (Rigon et al, 2009). There is some physiological evidence that NO is involved in behavior elicited by the tissue injury; NO-mediated signals seem to reduce nociception in the land snail Cepaea nemoralis (Kavaliers et al, 1998) and are important for long-term hyperexcitability after noxious stimulation in Aplysia (Lewin and Walters, 1999).…”

Neonatal Handling Impairs Spatial Memory and Leads to Altered Nitric Oxide Production and DNA Breaks in A Sex Specific Manner

“…By that day, free-floating sections were incubated in 0.1 M phosphate buffer containing 0.1% Triton X-100, 0.05% b-NADPH and 0.02% nitro blue tetrazolium at 37°C for 90 min [31]. All sections were then mounted onto gelatin-coated glass slides, air-dried, quickly colored with hematoxylin, cleared with xylene and cover slipped.…”

Estudios morfo-anatómicos y moleculares de <i>Megalobulimus</i> spp. (Gastropoda Pulmonata) en la Argentina, principalmente de la provincia de Misiones

“…1-14); Simone y Leme, 1998: 202;Bruschi-Figueiró y Veitenheimer-Mendes, 2002: 33;Campos Salgado y dos Santos Coelho, 2003: 157;Achaval et al, 2005: partim;Horn et al, 2005: partim;Simone, 2006: 206 (Fig. 779); Nóblega et al, 2006: partim;Kalil-Gaspar et al, 2007: partim;Rigon et al, 2009Rigon et al, , 2010Moraes et al, 2010: 341-343, 347, 348;Agudo-Padrón, 2011c: 30 ( Siqueira Dornellas y Simone, 2011: 2, 62, 73;Borda y Ramírez, 2013: 681;Martinez-Pereira et al, 2013: partim;Fontenelle et al, 2014: 31, 34 (Fig. 19).…”