Håkan Larsson

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Activation of GABA(B) receptors by the selective agonist baclofen produces anti-nociceptive effects in animal models of somatic pain. The aim of the present study was to evaluate the effect of baclofen and the GABA(B) receptor positive allosteric modulator CGP7930 on pseudo-affective responses to colorectal distension in rats. Female Sprague-Dawley rats(More)
Activation of cannabinoid receptors (CB(1), CB(2) and GPR(55)) produces analgesic effects in several experimental pain models, including visceral pain arising from the gastrointestinal tract. We assessed the role of CB(1), CB(2), and GPR(55) receptors and the endogenous cannabinoid system on basal pain responses and acute mechanical hyperalgesia during(More)
Transient receptor potential vanilloid 1 (TRPV1) channels have been implicated in pain mechanisms and, particularly, in the development of hyperalgesia. We used selective TRPV1 antagonists (NGV-1, SB-750364 and JYL 1421) to assess the role of TRPV1 channels in repetitive noxious colorectal distension (CRD)-induced visceral pain responses in rats. Isobaric(More)
Visceral hypersensitivity and stress have been implicated in the pathophysiology of functional gastrointestinal disorders. We used a selective vasopressin 3 (V(3)) receptor antagonist SSR149415 to investigate the involvement of the vasopressin (AVP)/V(3) signaling system in the development of stress-induced visceral hyperalgesia in rats. Rats were exposed(More)
Metabotropic glutamate 5 receptor (mGluR5) antagonists are effective in animal models of inflammatory and neuropathic pain. The involvement of mGluR5 in visceral pain pathways from the gastrointestinal tract is as yet unknown. We evaluated effects of mGluR5 antagonists on the colorectal distension (CRD)-evoked visceromotor (VMR) and cardiovascular responses(More)
Recordings of electromyographic (EMG) activity in the abdominal musculature are generally used to quantify the pseudo-affective visceromotor response induced by colorectal distension (CRD) in rodents. The present study describes a non-invasive, manometric method to quantify the magnitude of the abdominal contractions evoked by CRD. CRD-induced increases in(More)
The vanilloid-1 receptor TRPV1 is known to play a role in extrinsic gastrointestinal afferent function. We investigated the role of TRPV1 in mechanosensitivity in afferents from normal and inflamed tissue. Colonic mechanosensitivity was determined in an in vitro rat colon preparation by recording from attached splanchnic nerves. Recordings were made from(More)
It has been shown that the behavioural responses to chemically evoked visceral nociception are increased in transgenic mice lacking the kappa-opioid receptor (KOR). The aim of the present study was to evaluate the contribution of KOR in mechanically evoked visceral pain by performing colorectal distension (CRD) and monitoring the subsequent visceromotor(More)
We have investigated sensitization of reflexes in the isolated rat colon in order to develop a model that might prove useful for investigating how the sensitivity of enteric reflexes can be altered by prior stimulation. Records were taken of circular muscle tension, 7-10 mm oral and anal to radial distension exerted by a hook passed through the wall of the(More)
Previous in vivo experiments in rats have shown that pulsed nerve stimulations of 20-50 mV require "external" electrical communication over vessels. This indicates that potential differences also should occur in associated vessels, at physiologic muscle contractions. Pinching toes of the hind leg of anaesthetized rats in the present study caused the animals(More)