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Androstenone is a boar pheromone. and has also been found within different human body fluids. However, it is still unclear whether it carries pheromonal information in humans and whether it contributes significantly to the complex human body odor at all. Some humans fail to perceive the odor of androstenone, but most of these anosmics can achieve sensitivity by daily sniffing. The following study was designed to investigate whether sensitivity to androstenone influences the perception of body odors. Four females osmic to and four females anosmic to androstenone attended two EEG sessions. Anosmics were successfully sensitized to androstenone between sessions. CSERPs (chemosensory event-related potentials) were obtained while subjects perceived their own body odor and a male body odor within an olfactory oddball paradigm. The CSERPs showed a general decrease in amplitude from the first to the second session except for the sensitized anosmics in response to male body odor. The results indicate that the sensitivity to androstenone in females is associated with a stronger brain response to male body odor. more...

Human urine samples were fractionated to examine the contribution of volatiles to the individual body odor. The samples were obtained from 4 male donors and fractionated using a vacuum technique. The volatiles from the chemical fractions were analyzed using the CLSA technique and gas chromatography. Thereafter, these fractions were tested in a computer-controlled olfactometer by trained rats. Although the rats were able to discriminate the distillation residue, they could not recognize the urine odor in the distilled fraction. The results of gas chromatography indicate a continuous release of volatile constituents in the distillation residue. more...

Cholecystokinin (CCK) and related peptides are supposed to be potent analgesic neuropeptides. Studies in rodents suggest a dose-dependent biphasic effect. The present study aimed to examine the pain modulating effect of different doses (0.5 microgram and 5 micrograms) of ceruletide (CRL), infused i.v. for 30 min. Pain thresholds were obtained for ischemic, mechanical, and thermal pain. In addition, pain tolerance was measured for mechanical pain. According to a placebo-controlled double-blind within-subject design 25 healthy men attended three experimental sessions each. Pain perception was measured as a baseline and twice after the infusion. The effect of both doses of CRL to enhance the pain threshold for thermal stimuli is in line with former studies. However, perception of heat stimuli above or below the threshold was not substantially affected by CRL treatment. Algesic properties of CRL are also indicated, because the tolerance for mechanical pain decreased after administration of the high dose of CRL. Perception of ischemic pain was not obviously influenced by any of the treatments. The role of CRL in human pain modulation seems to vary, depending on the type of experimental pain. more...

The chemosensory identity of mice, rats, and humans is determined partly by polymorphic genes of the major histocompatibility complex (MHC). In inbred strains of mice as well as in seminatural populations MHC-associated mating preferences selectively influence reproductive success. To explore MHC-associated chemosignals in relation to otherwise genetically determined chemosignals a first study was conducted on seven trained rats' responses to the odors of inbred strains of mice. Results of the first study confirmed that neither the MHC nor genes in the genetic background dominate in determining urine odor specificity of mice and that specific olfactory cues associated with either the MHC or the genetic background can be identified by olfaction. In a second study, these specific olfactory cues were analyzed by means of gas chromatography. The results indicate that specific volatile components associated with either the MHC or the genetic background can be found in mouse urine odor, and that profiles of ubiquitous volatile components show some association with either the MHC or the genetic background. Furthermore, results show that a small number of specific compounds as well as a profile of some few ubiquitous volatiles constitute MHC-associated odor cues and that influences of the MHC and genes in the genetic background interact in constituting urine odor specificity in mice. more...