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Sexual mediators

The most important ecological role is probably played by the sexual mediators, which control the sequence of sexual processes for a number of marine animals. Other biological activities, such as alarm, trailing and individual or social recognition, also depend on this kind of mediator. [Pg.238]

The mammalian and avian immune systems function similarly both incorporate humoral and cell-mediated cytotoxic mechanisms, " and are thought to share a 160m year old relationship with the reptilian immune system. The immune system of mammals shows sexual dimorphism " a greater immune response is normally observed in females, which has been attributed to differences in steroid hormone concentration. In the toad Bufo regularis, sexual dimorphism of the immune system is also apparent. ... [Pg.73]

Central/Tertiary structures The fish olfactory bulb is a fourlayered structure much as in higher vertebrates. Within the 2nd layer, the first synapse for olfactory input is on the dendrites of the mitral cells (MC). About 1000 ORN axons converge on one MC, a ratio similar to mammals. The MC output, from cells at various levels, leads into several glomeruli and receives (inhibitory) input from granule cells. The latter also innervate a distinct cell type in the MC layer of teleosts — the ruffed cells (RC), with which they have reciprocal synapses [Fig. 2.18(a)] both relay cells send ascending fibres to forebrain centres (Kosaka and Hama, 1982). The RC are unlike the MC since they are not stimulated by the ORNs directly. Their interactions (Chap. 5) may contribute to the processing of pheromonal stimuli (Zippel, 2000). The main bulbar pathways project to several nuclei in the forebrain via two ipsilateral tracts, the lateral and medial [Fig. 2.18(b)], the latter mediates sexual behaviour and the former probably other behaviours (Hara,... [Pg.21]

Laukaitis C.M., Critser E.S. and Karin R.C. (1997). Salivary androgen-binding protein (ABP) mediates sexual isolation in Mus musculus. Evolution 51, 2000-2005. [Pg.223]

Sympathetic and parasympathetic nerves innervate the penis. In the flaccid state, OC2-adrenergic receptors mediate tonic contraction of the arterial and corporal smooth muscles. This maintains high penile arterial resistance and a balance exists between blood flow into and out of the corpora. With sexual stimulation, nerve impulses from the brain travel down the spinal cord to the thoracolumbar ganglia.3 A decrease in sympathetic tone and an increase in parasympathetic activity then occurs, causing a net increase in blood flow into the erectile tissue. Erections may also occur as a result of a sacral nerve reflex arc while patients are sleeping (nocturnal erections). [Pg.780]

Hillgarth, N. and Wingfield, J. C. 1997 Parasite-mediated sexual selection endocrine aspects. In Host-Parasite Evolution. General Principles and Avian Models (Clayton, D. H. and Moore, J., eds.). Oxford University Press, Oxford, pp. 78-104. [Pg.507]

McGraw, K. J. and Parker, R. S. 2006. A novel lipoprotein-mediated mechanism controlling sexual attractiveness in a colourful songbird. Physiol. Behav. 87 103-108. [Pg.508]

Flowers of some orchids mimic both the appearance and sex pheromone of virgin females of certain species of bees or wasps. This sexual deception results in pollination by male hymenoptera that would not normally visit flowers. Japanese honey bee drones (Apis cerana japonica) cluster on the oriental orchid (Cymbidiumpumilum) while on their mating flights [ 134]. By comparing volatile profiles of orchids and the female hymenoptera they mimic, or by GC-EAD and GC-MS analysis of orchid volatiles, several compounds have been identified that may mediate this attraction for the solitary bee Andrena nigroaenea [135, 136] and the scoliid wasp Campsoscolia ciliata [135]. [Pg.173]

Penn, D. and Potts, W.K. (1998) Chemical signals and parasite-mediated sexual selection. Trends Ecol. Evolut. 13, 391-396... [Pg.160]

LeMaster, M.P. and Mason, R.T. (2003) Pheromonally mediated sexual isolation among denning populations of red-sided garter snakes, Thamnophis sirtalis parietalis. J. Chem. Ecol. 29, 1027-1043. [Pg.230]

Which olfactory system mediates sexual behavior in mice has also been a matter of debate. Early studies (Thompson and Edwards 1972 Edwards and Burge 1973) suggested a role for the main olfactory system in the display of female sexual receptivity, since destructions of the MOE by intranasal infusion with a zinc sulfate solution (ZnS04) attenuated lordosis behavior in estrogen-progesterone-treated mice. However, the VNO may be also involved as a reduction in female sexual receptivity by VNO removal has been reported in various other rodent species (rats Rajendren,... [Pg.243]

O Connell, RJ. and Meredith, M. (1984) Effects of volatile and nonvolatile chemical signals on male sexual behaviors mediated by the main and accessory olfactory systems. Behav. Neurosd. 98, 1083-1093. [Pg.250]

Powers, J.B. and Winans, S.S. (1975) Vomeronasal organ critical role in mediating sexual behavior of the male hamster. Science 187, 961-963. [Pg.250]

Our laboratory has begun to determine if this phenomenon of experience-dependent attraction to male volatile cues also occurs in female Syrian hamsters, as experiential effects on odor preference may vary according to species. Syrian hamsters provide an ideal model species for studying sexual preference as these behaviors are almost exclusively mediated by chemosensory cues (Johnston 1983). Furthermore, both males and females display robust preferences for opposite-sex volatile odors that are independent of adult sexual experience (Landauer, Banks and Carter 1977 Petrulis and Johnston 1999), suggesting that early olfactory experience may play a critical role in the development of these behaviors. [Pg.256]

Taken together, this body of work demonstrates that adult behavioral responses to social odors are shaped by early olfactory experience. Indeed, heterospecific or artificial odor cues associated with the rearing environment acquire attractive properties that can last into adulthood in many rodent species. Furthermore, early experience with opposite-sex odors appears to be critical for the normal development of appropriate behavioral responses to sexual odors in mice and hamsters. Importantly, the behavioral plasticity observed using these different experimental approaches may all be mediated by a classical conditioning model of olfactory learning. The experience-dependent development of odor preference in rodents therefore provides a powerful model for understanding how the olfactory system recognizes and learns the salience of social odors, a function that is critical for the appropriate expression of reproductive behavior. [Pg.258]

Sexual Pheromones Mediate Intersexual Attraction in Mice... [Pg.262]


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See also in sourсe #XX -- [ Pg.238 ]




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