Biomedical subjects

Volker Limmroth

Publications and source records attributed to Volker Limmroth.

21 records · Page 2Linked to original sources

PubMed2002

Behaviorally conditioned immunosuppression in the rat is regulated via noradrenaline and beta-adrenoceptors.

Using Cyclosporin A (CsA) as an unconditioned stimulus has previously demonstrated that behaviorally conditioned inhibition of splenocyte proliferation and cytokine production is mediated via the splenic nerve. Therefore, we currently examined the adrenergic modulation of conditioned suppression of splenocyte function. Chemical sympathectomy via 6-OHDA completely blocked the conditioned suppression of splenocyte proliferation to mitogens and cytokine (IL-2, IFN-gamma) production. Furthermore, administration of beta-adrenoceptor antagonist propranolol abrogated the conditioned effect on splenocyte proliferation. Supporting the position that conditioning is beta-adrenergic-dependent, addition of beta-adrenoceptor agonist, but not alpha-adrenoceptor agonists, to splenocytes in vitro mimicked the conditioned suppression of splenocyte functions, with these effects blocked by propranolol. Therefore, these data indicate that behavioral conditioning of splenocyte function in the rat is regulated by the sympathetic nervous system, predominantly via beta-adrenergic mechanisms.

Adrenergic beta-Agonists↗

PubMed2002

Neuropsychological performance and mood states following acute interferon-beta-1b administration in healthy males.

Interferon-beta-1b (IFN-beta-1b) has been shown to reduce the relapse rate in patients with relapsing-remitting multiple sclerosis (MS) and disease progression in patients with secondary progressive MS. While acute administration of IFN-beta-1b is known to cause flu-like symptoms, chronic medication has been suggested to cause mood alterations and anxiety attacks, and secondary to this neuropsychological deficits that may impair daily life. It is unknown, however, whether the latter symptoms are induced by acute IFN-beta-1b administration. Therefore, we examined the impact of a single subcutaneous injection of IFN-beta-1b in 8 healthy males. In a crossover design, each subject was injected subcutaneously with either 8 million IU IFN-beta-1b or placebo (NaCl) at 8:00 h. Flu-like symptoms (body temperature, heart rate, blood pressure), mood status ['profile of mood states', Befindlichkeitsskala (BFS)] and neuropsychological performance (trail marking test, verbal memory test, d2 attention test) and were assessed at baseline, 4, 8 and 24 h after injection. IFN-beta-1b increased body temperature, heart rate and fatigue. Nevertheless, acute IFN-beta-1b injection did not impair any parameters of neuropsychological performance. Thus, although IFN-beta-1b produces physiological symptoms indicative of sickness behavior, these data suggest that IFN-beta-1b administration does not have an impact on the cognitive capacity following acute administration.

Adult↗

PubMedDate not supplied

A novel method of eliciting pain-related potentials by transcutaneous electrical stimulation.

BACKGROUND: Electrophysiological techniques such as laser and contact heat evoked pain-related potentials are very useful for studying trigeminal and somatic pain transmission in humans. These methods are, however, partly invasive, expensive, and therefore not available for broad clinical use. We recently proposed a novel technique of noninvasive transcutaneous electrical stimulation. OBJECTIVE: To elicit pain-related evoked potentials (PREP) by using a concentric planar electrode and demonstrate their nociceptive specificity. METHODS: We registered PREP following stimulation of the forehead and hand in 14 healthy volunteers. Latencies, peak-to-peak amplitudes, and conduction velocities of nociceptive fibers have been estimated. Effects of temporal and spatial summation and of cutaneous anesthesia were evaluated. RESULTS: Stimulation with the concentric planar electrode produced pinprick-like painful sensation. Cutaneous anesthesia led to abolishment of PREP responses. Estimated mean conduction velocity was 11.61 +/- 5.12 m/s, which corresponded well with conduction via A-delta fibers. Spatial as well as temporal summation resulted in a parallel increase of perceived pain intensity and PREP amplitudes. CONCLUSION: The technique is noninvasive, affordable, and easy to perform and allows quantitative assessment of human nociceptive pathways.

Adult↗