Comparative ultrastructure of plasmodesmata of Chara and selected bryophytes: towards an elucidation of the evolutionary origin of plant plasmodesmata

We have used transmission electron microscopy to examine plasmodesmata of the charophycean green alga Chara zeylanica, and of the putatively early divergent bryophytes Monoclea gottschei (liverwort), Notothylas orbicularis (hornwort), and Sphagnum fimbriatum (moss), in an attempt to learn when seed plant plasmodesmata may have originated. The three bryophytes examined have desmotubules. In addition, Monoclea was found to have branched plasmodesmata, and plasmodesmata of Sphagnum displayed densely staining regions around the neck region, as well as ring-like wall specializations. In Chara, longitudinal sections revealed endoplasmic reticulum (ER) that sometimes appeared to be associated with plasmodesmata, but this was rare, despite abundant ER at the cell periphery. Across all three fixation methods, cross-sectional views showed an internal central structure, which in some cases appeared to be connected to the plasma membrane via spoke-like structures. Plasmodesmata were present even in the incompletely formed reticulum of forming cell plates, from which we conclude that primary plasmodesmata are formed at cytokinesis in Chara zeylanica. Based on these results it appears that plasmodesmata of Chara may be less specialized than those of seed plants, and that complex plasmodesmata probably evolved in the ancestor of land plants before extant lineages of bryophytes diverged

Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study [ISRCTN70707830]

BACKGROUND: Fibromyalgia syndrome displays sympathetically maintained pain features such as frequent post-traumatic onset and stimuli-independent pain accompanied by allodynia and paresthesias. Heart rate variability studies showed that fibromyalgia patients have changes consistent with ongoing sympathetic hyperactivity. Norepinephrine-evoked pain test is used to assess sympathetically maintained pain syndromes. Our objective was to define if fibromyalgia patients have norepinephrine-evoked pain. METHODS: Prospective double blind controlled study. Participants: Twenty FM patients, and two age/sex matched control groups; 20 rheumatoid arthritis patients and 20 healthy controls. Ten micrograms of norepinephrine diluted in 0.1 ml of saline solution were injected in a forearm. The contrasting substance, 0.1 ml of saline solution alone, was injected in the opposite forearm. Maximum local pain elicited during the 5 minutes post-injection was graded on a visual analog scale (VAS). Norepinephrine-evoked pain was diagnosed when norepinephrine injection induced greater pain than placebo injection. Intensity of norepinephrine-evoked pain was calculated as the difference between norepinephrine minus placebo-induced VAS scores. RESULTS: Norepinephrine-evoked pain was seen in 80 % of FM patients (95% confidence intervals 56.3 – 94.3%), in 30 % of rheumatoid arthritis patients and in 30 % of healthy controls (95% confidence intervals 11.9 – 54.3) (p < 0.05). Intensity of norepinephrine-evoked pain was greater in FM patients (mean ± SD 2.5 ± 2.5) when compared to rheumatoid arthritis patients (0.3 ± 0.7), and healthy controls (0.3 ± 0.8) p < 0.0001. CONCLUSIONS: Fibromyalgia patients have norepinephrine-evoked pain. This finding supports the hypothesis that fibromyalgia may be a sympathetically maintained pain syndrome