Response characteristics of nucleus submedius neurons to colo-rectal distension in the rat

Kawakita, Kenji; Sumiya, Eiji; Murase, Kentaro; Okada, Kaoru

doi:10.1016/s0168-0102(97)01177-2

Cited by 14 publications

(9 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present study, only distention of the distal descending colon was tested. Responses were found in similar thalamic subregions (see RESULTS) as reported in three previous studies (see Berkley et al 1993b;Kawakita et al 1997;Yang et al 1998). In the present study, however, only 18% of the neurons in these subregions responded.…”

Section: Discussionsupporting

confidence: 87%

Responses of Thalamic Neurons to Input From the Male Genitalia

Hubscher

Johnson

2003

Journal of Neurophysiology

View full text Add to dashboard Cite

There have been relatively few electrophysiological studies, in any species, describing the supraspinal processing of inputs from the male genital tract. The thalamus was the focus of the present study. In 11 urethan-anesthetized male rats, subregions of the thalamus were surveyed for neuronal responses to the search stimulus, bilateral electrical stimulation of the dorsal nerve of the penis (DNP). A total of 133 DNP-responsive neurons were found and further tested for degree of somatovisceral convergence from other peripheral structures. Histological reconstruction of the recording sites revealed that the penile-responsive neurons were distributed among various thalamic subregions. These thalamic subregions included the medial-dorsal nuclei and ventral and lateral thalamic subregions (majority of neurons responsive to both tactile and pinch stimulation of the penis) as well as intralaminar, posterior and reticular subregions (majority responsive to pinch only). Taken together, the data demonstrate the existence of thalamic neurons with inputs from the male genitalia with widespread somatovisceral convergence. These neurons likely contribute to the neural circuitries underlying various aspects of penile sensation associated with reproductive and nociceptive events.

show abstract

Section: Discussionsupporting

confidence: 87%

Responses of Thalamic Neurons to Input From the Male Genitalia

Hubscher

Johnson

2003

Journal of Neurophysiology

View full text Add to dashboard Cite

show abstract

“…The Sm is located at the medial thalamus, which is thought to be involved in motivational and affective aspects of pain (see Craig and Burton, 1981). Neurons recorded from the Sm responded to noxious stimuli (Craig and Burton, 1981; Kawakita et al, 1993), notably to noxious input associated with deep tissue injury and inflammation (Dostrovsky and Guilbaud, 1990; Kawakita et al, 1997). Our data support a role of the Sm in processing orofacial deep noxious input.…”

Section: Discussionmentioning

confidence: 99%

Differential rostral projections of caudal brainstem neurons receiving trigeminal input after masseter inflammation

Ikeda

Terayama

Jue

et al. 2003

J of Comparative Neurology

View full text Add to dashboard Cite

To understand the functional significance of orofacial injury-induced neuronal activation, this study examined the rostral projection of caudal brainstem neurons that were activated by masseteric inflammation. Rats were injected with a retrograde tracer, Fluorogold, into the nucleus submedius of the thalamus (Sm), parabrachial nucleus (PB), lateral hypothalamus (LH), or medial ventroposterior thalamic nucleus (VPM) 7 days before injection of an inflammatory agent, complete Freund's adjuvant (CFA), into the masseter muscle. Rats were perfused at 2 hours after inflammation, and brainstem tissues were processed for Fos-Fluorogold double immunocytochemistry. Although there was no difference in Fos expression among the four groups (n=4 per site), the rostral projection of Fos-positive neurons showed dramatic differences. In the ventral portion of the trigeminal subnuclei interpolaris/caudalis (Vi/Vc) transition zone, the percentage of Fos-positive neurons projecting to the Sm (39.7%) was significantly higher than that projecting to the LH (5.4%) or VPM (5.6%; P<.001). The anesthesia alone also induced Fos expression in ventral Vi/Vc neurons, but these neurons did not project to Sm. In the caudal laminated Vc and dorsal Vi/Vc, the PB was the major site of rostral projection of Fos-positive neurons. In the caudal ventrolateral medulla and nucleus tractus solitarius, Fos-positive neurons projected to the Sm, PB, and LH. Most VPM-projecting neurons examined did not show Fos-like immunoreactivity after masseter inflammation. These findings emphasize the importance of the trigeminal Vi/Vc transition zone in response to orofacial deep tissue injury. Furthermore, the results differentiate the ventral and dorsal portions of the Vi/Vc transition zone, in that the Sm received projection mainly from activated neurons in the ventral Vi/Vc. The activation of Vi/Vc neurons and associated ascending pathways may facilitate somatoautonomic and somatovisceral integration and descending pain modulation after orofacial deep tissue injury.

show abstract

“…For example, a recent electrophysiological study by Ito (1998) in the rat, suggests that the insula (dorsal insular cortex) receives convergent sensory input from both the viscera and body surface, and the latter probably conveys somatic nociceptive information. Kawakita et al, (1997) explored the effects of colorectal distension in the rat on neurons located in and around the nucleus submedius (Sm) in the medial thalamus. The results of their electrophysiological study demonstrate that most of the Sm neurons receive convergent viscerosomatic inputs from the colon and/or rectum and from the skin, suggesting that the Sm may participate in visceral nociception.…”

Section: Pathophysiological Aspectsmentioning

confidence: 99%

Recent and forgotten aspects of visceral pain

Giamberardino

1999

European Journal of Pain

146

View full text Add to dashboard Cite

Progress in the field of visceral pain research has been particularly rapid in recent years. Some aspects of the symptom that had previously been neglected for some time have now received a great deal of attention in both clinical and experimental studies. This regards, in particular, phenomena of hyperalgesia: (a) of visceral structures, because of local inflammatory/sensitizing processes (visceral hyperalgesia); (b) of areas of referred pain from viscera (referred somatic hyperalgesia from viscera); and (c) of a visceral structure, because of an algogenic process of another visceral domain (viscero-visceral hyperalgesia). Clinical studies in patients have led to characterisation of subjective and objective symptoms of these phenomena. A number of studies in human volunteers (employing experimental procedures to stimulate and measure pain reactivity in both visceral structures and somatic areas of referral) have further increased the knowledge about modalities of generation of the various forms of hyperalgesia.Animal experiments have improved understanding of pathophysiological mechanisms, mostly those underlying the referred hyperalgesia, with a number of findings supporting the notion of central changes at the basis of the phenomenon. An important aspect of laboratory experiments in recent years has been the setting up of animal models of visceral pain conditions closely mimicking a number of clinical pain states in patients. As a result, the outcome of experimental studies (electrophysiological, pharmacological, etc.) appears more directly applicable to the interpretation of the clinical reality.Finally, in the context of laboratory studies, a novel trend of investigation is represented by genetic experiments, particularly those employing 'knock-out' mice. These experiments, by generating animals lacking specific genes responsible for the production of various receptors implicated in pain transmission, have further contributed to the understanding of the generation of visceral pain symptoms. Although studies in this field are in their early stage, they seem particularly promising for a better understanding of the pathophysiology of visceral pain, and thus the establishment of more satisfying therapies in the future. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

show abstract

Response characteristics of nucleus submedius neurons to colo-rectal distension in the rat

Cited by 14 publications

References 30 publications

Responses of Thalamic Neurons to Input From the Male Genitalia

Responses of Thalamic Neurons to Input From the Male Genitalia

Differential rostral projections of caudal brainstem neurons receiving trigeminal input after masseter inflammation

Recent and forgotten aspects of visceral pain

Contact Info

Product

Resources

About