Olfactory notes

The production of a female-influencing secretion from the chin gland of male Plethodontid salamander (P. jordani) points to a similar extension of function by the acquisition of female olfactory sensitivity to an intercellular signal protein. Female receptivity is enhanced by a male cytokine-like compound of the interleukin-6 family, in its released form. Rollman et al. (1999) note that pheromonal activity is a previously unrecognised function for cytokines. 

Flehmen in all species so far studied is stereotyped in execution, although as noted, not all typical patterns are part of each species repertoire. Its function(s) may well vary with species requirements, as with the modifications in certain antelopes discussed above (Hart et al., 1988). F. is not always dimorphic and can be influenced by social context the licking/lapping sequence aids discriminations among female as well as male lemurs [Fig. 7.9(a)]. The contribution of F. to fertility is bound up with the role of the AOS in reproductive patterns. Not all species with a full complement of accessory olfactory structures have been scrutinised for F., nevertheless it is rarely absent, even if modified, in species with VNO/AOB presence. Its presence has not been reported in species without a functional AOS, as required by Knappe s hypothesis (Knappe, 1964). 

With regard to the odor threshold for hydrogen sulfide, it should be noted that although odor can be perceived at 0.5 ppb in air, olfactory fatigue can occur at concentrations of 100 ppm or greater causing a loss of odor perception (Leonardos et al. 1969). 

Current evidence strongly suggests the existence of olfactory cues to ovulation in humans. Such cues could be used by men for monitoring their current or potential partner. It should be noted, however, that men cannot determine ovulation exactly but rather in a probabilistic manner. Therefore we believe that cyclic odour cues are rather a byproduct of physiological changes than a specific signal of ovulation. 

The remarkable similarity of glomerular organization in the first-order central olfactory neuropils of essentially all invertebrates and vertebrates that have a differentiated olfactory system has been noted often (e.g., refs. 9-12). Indeed, Dethier (1) argued persuasively that olfactory systems similar to those of contemporary insects and vertebrates, with comparable glomerular organization, were probably already in place 500 million years ago. Referring to environmental odor substances produced, first by photosynthesis and later by mankind s organic chemistry, in varieties far... 

Even marine mammals may use airborne odors for food detection. Baleen whales (Mysticeti) feed on krill near the ocean s surface. Oldtime Antarctic whalers noted a krill odor near large schools of krill. Cruising at the surface and inhaling periodically, baleen whales may detect krill odor. Anatomically, they have a well-developed olfactory organ (Cave, 1988), in contrast to toothed whales (Kusnetzov, 1988). 

Cave, A. J. E. (1988). Note on olfactory activity in mysticetes. Proceedings of theZoologicalSoci-ety of London, 214,307-311. 

Abdominal cramps, vomiting, and diarrhea occurred in a truck driver who was exposed to diesel fuel vapor for 10 days while driving a truck with a leaking fuel injector. Acute renal failure was also observed. One case study describes eye irritation in two individuals exposed to JP-5 fuel (kerosene) for approximately 1 hour while flying an airplane. Coordination and concentration difficulties were noted, as were headache, apparent intoxication, and anorexia. Inhalation of 140mg/m deodorized kerosene by six volunteers caused olfactory fatigue in three subjects and a taste sensation in... 

In an intermediate-duration inhalation study of nickel sulfate in rats (Dunnick et al. 1989 NTP 1996c), alveolar macrophage hyperplasia was observed at all concentrations (0, 0.03, 0.06, 0.11, 0.22, and 0.44 mg nickel/m ), and chronic active inflammation of the lungs and olfactory epithelial atrophy were noted at 0.6 mg/m. Macrophage hyperplasia tends to be an inconsistent or perhaps reversible effect that showed an increase after 7 months of exposure but not at 2 years in the chronic study. In addition to being a minimal or reversible effect, alveolar macrophage hyperplasia can be attributed to the physical stimulus of particulate treatment and is not necessarily speciflc for nickel. Therefore use of 0.03 mg/m as a LOAEL for macrophage hyperplasia to derive an intermediate MRL is questionable. Because the NOAEL identified in the chronic study (0.03 mg/m ) is at the level of a minimal LOAEL in the intermediate-duration study, the chronic MRL should be protective of both chronic- and intermediate-duration exposures. 

Body weights of female rats were 6-9% lower than controls during the second year. Hematology examinations completed at a 15 month interim sacrifice showed no effects. The only treatment-related changes noted were in the respiratory tract. Minimal to mild chronic active inflammation was observed at all concentrations at the 7 month interim sacrifice, but only at the two higher concentrations at two years. The inflammation was described as multifocal, minimal to mild accumulations of macrophages, neutrophils and cell debris within alveolar spaces. Fibrosis was observed in 2/54, 6/53, 35/53 and 43/53 male rats, and 8/52, 7/53, 45/53, and 49/53 female rats at 0, 0.03, 0.06, and 0.11 mg/m, respectively. Hyperplasia of the bronchial lymph nodes and atrophy of the olfactory epithelium were observed at the high dose. 

Norepinephrine may also play a role in the induction of immediate early genes in response to pup exposure (Thomas and Palmiter, 1997). Norepinephrine has been linked to maternal behavior in certain other animal models, such as sheep and rats. It may also play a role in olfactory recognition and memory in rats. Intraventricular administration of 6-OHDA prior to birth has been noted to impair postpartum maternal behavior administration after birth had no such effect. 

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