Dynamic variations of c‐Fos expression in the spinal cord exposed to intramuscular hypertonic saline‐induced muscle nociception

Abstract

It is suggested that spinal nociceptive neuronal activities in superficial and deep layers may differently be modulated by endogenous descending facilitation and inhibition, respectively.

Effects of simulated weightlessness on intramuscular hypertonic saline induced muscle nociception and spinal Fos expression in rats

“…unilateral noxious stimuli elicited Fos expression in both sides of the spinal DH (Hunt et al, 1987;Ji and Rupp, 1997;Chen et al, 2013). The simulated weightlessness alone induced spinal Fos expression, which is in line with the results of earlier studies indicating that the currently used HU model alone significantly enhanced spinal Fos expression (Langlet et al, 2001;Yang et al, 2008).…”

“…5). It has been proposed in earlier studies that neurons within superficial and deeper layers of the spinal DH are regulated by descending facilitatory and inhibitory controls, respectively (McMahon and Wall, 1988;Bett and Sandkühler, 1995;You et al, 2006You et al, , 2009Chen et al, 2013). Based on these earlier and the present findings, it may be speculated that the enhancement of the Fos response to i.m.…”

“…hypertonic (HT; 5.8%) saline-induced increases in Fos expression in the superficial layers (laminae I-II) and the deep layers (laminae V-VI) of the spinal DH are significantly lower and higher, respectively, in spinalized than intact rats. This observation provides evidence that activities of spinal nociceptive neurons in superficial and deep layers of the spinal DH may be modulated by endogenous descending facilitation and inhibition, respectively (Chen et al, 2013).…”

Electromyography and Fos immunostaining study establish a possible functional link between trigeminal proprioception and the oculomotor system in rats

“…Furthermore, it is known that following functional related stimulation, c-Fos oncogene and Fos proteins are usually expressed along the functional pathway [29] . For example, taste related stimulation induced Fos expression in neurons along the visceral sensation central pathway [30-31] ; however, nociceptive stimulation evoked Fos production among neurons of the nociception conveying central pathway [32-33] . As aforementioned, down-stretching of the lower jaw predominantly motivates jaw muscle spindle afferents [26-27] ; therefore, Fos expression should be associated with trigeminal proprioception conductance.…”

Injections of Algesic Solutions into Muscle Activate the Lateral Reticular Formation: A Nociceptive Relay of the Spinoreticulothalamic Tract

“…While the present c-Fos data mimics that presented by two studies focusing on the spinal cord after stimulation of the GCM [ 19 , 21 ], our data differs markedly from that of other c-Fos studies after algesic injection of muscle. Two studies [ 57 , 58 ] showed little c-Fos immunoreactivity, while another [ 59 ] showed thousands of immunoreactive profiles bilaterally in all spinal laminae. These discrepancies may be due to differing levels of labeling sensitivity that are intrinsic to individual laboratories.…”