Colorectal distension-induced pseudoaffective changes as indices of nociception in the anesthetized female rat: Morphine and strain effects on visceral sensitivity

Evaluation of pressor and visceromotor reflex responses to bladder distension in urethane anesthetized rats

“…5 Interestingly, both distension-induced hypotension and distension-induced hypertension in urethane anesthetized rats were observed in colorectal distension model. 6,9 The discrepancy may be due to different experimental conditions including time course post urethane injection.…”

“…8 Therefore, in maintaining a stable and light anesthesia, urethane would provide a relatively easy control if it replicates the pattern of the nociceptive responses seen in isoflurane anesthetized animals. 9 The pseudoaffective responses were found to be intact in decerebrate animals, 4,6,10 but were diminished or altered under the influence of anesthesia. 6 Interestingly, urethane anesthesia has been applied in the colorectal distension model of cardiovascular and VMR responses 9,11 and was reported to mimic nociceptive responses seen in awake rats by Ness and Gebhart.…”

“…9 The pseudoaffective responses were found to be intact in decerebrate animals, 4,6,10 but were diminished or altered under the influence of anesthesia. 6 Interestingly, urethane anesthesia has been applied in the colorectal distension model of cardiovascular and VMR responses 9,11 and was reported to mimic nociceptive responses seen in awake rats by Ness and Gebhart. 6 However, the effects of anesthetics are involved in the inhibition of multiple neurotransmitter-gated ion channels.…”

Comparison of cystometric methods in female rats

“…These are responsive to stimulus intensity 17,18 and have been demonstrated to be preserved under urethane anesthesia in rats. 19 They are thus useful endpoints for the study of the effect of cystometry on voiding.…”

The Selective 5-Hydroxytryptamine 1A Antagonist, AZD7371 [3(R)-(N,N-Dicyclobutylamino)-8-fluoro-3,4-dihydro-2H-1-benzopyran-5-carboxamide (R,R)-tartrate Monohydrate] (Robalzotan Tartrate Monohydrate), Inhibits Visceral Pain-Related Visceromotor, but Not Autonomic Cardiovascular, Responses to Colorectal Distension in Rats

“…Pseudoaffective autonomic cardiovascular responses (changes in heart rate and blood pressure) have been characterized as a component of the pain response (Ness and Gebhart, 1988;Sivarao et al, 2007;Brusberg et al, 2008Brusberg et al, , 2009bLindström et al, 2008;Ravnefjord et al, 2008), probably generated at higher CNS centers primarily in the brainstem where the primary integration of ascending pain-related signals is likely to occur and autonomic cardiovascular centers are located (Loewy and McKellar, 1980;Martínez et al, 2006). Nevertheless, cardiovascular responses have been used to a lesser extent than the VMR as a surrogate marker for pain.…”