Immunohistochemical evidence for the Na⁺/Ca²⁺exchanger in squid olfactory neurons

Abstract

The olfactory organs from the squid Lolliguncula brevis are composed of a pseudostratified epithelium containing five morphological subtypes of chemosensory neurons and ciliated support cells. Physiological recordings have been made from two of the subtypes and only the type 4 neuron has been studied in detail. Odour-stimulated increases in intracellular calcium and rapid activation of an electrogenic Na+/Ca2+ exchanger current in type 4 neurons suggest that the exchanger proteins are localized very close to the transduction machinery. Electrophysiological studies have shown that olfactory signal transduction takes place in the apical ciliary regions of olfactory neurons. Using polyclonal antiserum against squid Na+/Ca2+ proteins, we observed specific staining in the ciliary region of cells that resemble type 2, 3, 4 and 5 neurons. Staining was also observed in axon bundles, and in muscle tissue. Collectively, these data support the model that Na+/Ca2+ exchanger proteins are localized to transduction machinery in cilia of type 4 neurons and suggest that the other olfactory subtypes also use Ca2+ during chemosensory responses.

Time course of structural and functional maturation of human olfactory epithelial cells in vitro

“…Although it is generally accepted that odorant‐elicited [Ca 2+ ] i increases are mediated by an influx of Ca 2+ through the second‐messenger‐gated channels and through voltage‐gated Ca 2+ channels (for review see Schild and Restrepo, ), the mechanism for eliciting an odorant‐elicited decrease in [Ca 2+ ] i is still unknown. There is strong evidence for the involvement of Na + /Ca 2+ exchangers in olfactory neurons (Noe et al, ; Lucero et al, ), which likely mediate Ca 2+ extrusion and the subsequent cellular adaptation following stimulation (Jung et al, ; Reisert and Matthews, , ). Because the mechanisms for driving increases or decreases in [Ca 2+ ] i are very different, it is possible that these mechanisms develop separately and that the mechanism for expression of cellular components for calcium removal from the cytosol is functional prior to the development of second messenger systems (the voltage‐gated channels are developed and functional by day 3, as shown in Fig.…”

Role of olfaction in Octopus vulgaris reproduction

“…The anatomical descriptions of a putative olfactory organ in cephalopods first appeared in early literature (von Kölliker, 1844), followed by more recently demonstrations of their chemosensory capabilities and sensory mechanisms. To date, what is known about the olfactory organ in cephalopods comes from studies of Nautilus (Basil et al, 2000;Ruth et al, 2002) and decapods (Lucero and Gilly, 1995;Lucero et al, 1992Lucero et al, , 2000Mobley et al, 2007Mobley et al, , 2008aPiper and Lucero, 1999;Villanueva and Norman, 2008). In squid the olfactory organ is the site of a sensory epithelium resulted of ciliated supporting cells and different types of receptor cells that are bipolar neurons sending an dendritic stalk branch to the surface of the epithelium where sensory cilia are exposed to the marine environment.…”

“…Olfaction plays a role in mate choice of squid and cuttlefishes (Cummins et al, 2011;Gilly and Lucero, 1992;Lucero and Gilly, 1995;Lucero et al, 1992Lucero et al, , 2000Mobley et al, 2007;Piper and Lucero, 1999;Zatynly et al, 2000) and improves predation on crabs by cuttlefishes (Boal et al, 2000). Nautilus use olfaction for distant food odour detection and location, and perhaps for mate choice (Basil et al, 2000;Ruth et al, 2002).…”

Plasma membrane Ca2+‐ATPase in the cilia of olfactory receptor neurons: possible role in Ca2+ clearance

“…However, single K Ca recordings in membrane patches excised from olfactory cilia showed that in the vicinity of the plasma membrane Ca 2+ may reach much higher values, close to 100 lm (Delgado & Bacigalupo, 2004). Functional evidence indicates that a Na + ⁄ Ca 2+ exchanger (NCX) localizes to the cilia, extruding Ca 2+ after an odour stimulus (Reisert & Matthews, 1998;Danaceau & Lucero, 2000;Lucero et al, 2000).…”