Thesis (Ph.D.)--Uniformed Services University of the Health Sciences, 2006 / Typescript (photocopy)

The present series of studies was undertaken to determine the effects of peripherally and centrally administered alpha-melanocyte stimulating hormone (MSH) on lordosis and to investigate some of the mechanisms underlying these effects. The results of Experiments 1-5 (Section I) indicated that, when confounding factors were minimized, peripherally administered MSH facilitated receptivity. Centrally administered MSH was found to produce both a long and a short term inhibitory effect. Experiment 6 (Section II) tested the hypothesis that the facilitatory action of peripherally administered MSH was due to an MSH-induced release of progesterone or some other facilitatory adrenal steroid. Results indicated that, while adrenalectomy per se did not inhibit lordosis, it blocked the facilitatory action of MSH, supporting the hypothesis. In Experiments 7-9 (Section III), the role of estrogen and progesterone in the inhibitory actions of MSH was examined. The results of these studies suggested that both estrogen and progesterone are necessary for the short term inhibitory action of MSH. However, the long term inhibitory action of MSH appears to be due, in part, to an MSH-induced decrease in the availability of cytoplasmic progestin receptors. In Experiments 10-15 (Section IV), the role of serotonin in the production of the inhibitory actions of MSH was examined. Parachlorophenyl-alanine (PCPA), a serotonin depletor, was found to prevent the long term inhbitory action of MSH. In addition, the inhibitory effects of PCPA or pirenperone, a serotonin type II receptor antagonist, did not summate with the inhibitory action of MSH. This suggested that serotonin type II receptors were involved in the production of the inhibitory actions of MSH. In Experiment 12, quipazine, a serotonin type II agonist, was found to attenuate fully the short term Inhibitory action of MSH. However, quipazine did not fully attenuate the long term inhibitory action of MSH, suggesting that the short and long term inhibitory actions of MSH are mediated through different mechanisms. This possibility was supported by the results of Experiment 13, which indicated that 20 ng MSH produced a long term, but not a short term, inhibitory effect. The results of Experiment 14 indicated that subthreshold doses of pirenperone and of MSH, when administered together, would inhibit receptivity. Experiment 15 indicated that this inhibition could be attenuated by quipazine. Thus, the following conclusions can be drawn: 1) the facilitatory action of peripherally administered MSH is probably mediated by an MSH-induced release of progesterone from the adrenals, 2) the short term inhibitory action of MSH is mediated, to a large extent, by an MSH-induced decrease in serotonin type II activity, and 3) the long term inhibitory action of MSH is mediated, in part, by an MSH/serotonin-induced decrease in the availability of progestin receptors. In addition, it was hypothesized that: 1) progesterone acts in the MRF to increase serotonin type II activity. Thus, MSH-induced decreases in serotonin type II activity and in progestin receptors probably occur at this location, and 2) estrogen acts in the AH-POA to decrease serotonin type I activity. Therefore, any actions of MSH on serotonin type I activity or on estrogen receptors is likely to occur in this region. Finally, it was suggested that MSH plays a role in the induction and maintenance of pseudopregnancy, thereby providing MSH with a functional role in the regulation of receptive states. / Arts, Faculty of / Psychology, Department of / Graduate

The genetic relationship of anadromous (sockeye salmon) and non-anadromous (kokanee) Oncorhynchus nerka was examined in conjunction with the breeding behaviour of the two forms to determine: (1) if there is evidence of genetic divergence between the forms where they spawn sympatrically; (2) if such divergence is associated with significant premating isolation between the forms and; (3) if premating isolation results directly from the size difference between the forms (sockeye are much larger than kokanee at maturity). Both sexes exhibit spawning territoriality; females establish and defend particular nest sites until death or displacement, males defend access to specific females from other males until the female has spawned out, they are displaced, or leave to compete for additional mates. Size and prior access to resources (mates and/or specific areas) are significant factors in intrasexual aggression in both sexes, with size the major factor in males and prior access the major factor in females. Females accompanied by males larger than themselves lose weight at a faster rate than those accompanied by males smaller than themselves. Weight loss is related to egg loss, indicating females spawn at a faster rate when accompanied by large males. Male mate preference depends on the size of the male. Males of various sizes prefer females of their own size or larger over females smaller than themselves. In contrast, all sizes of males tested demonstrated no preference between females of their own size and those larger. Large males, which have the widest range of potential mates (because of male intrasexual competition and female choice), are the most selective and small males, which have the narrowest range of potential mates, are the least selective. There were significant differences in allele frequencies between sympatrically spawning sockeye and kokanee. However, there were no consistent differences between sockeye and kokanee at any of five polymorphic loci examined. The extent of genetic differentiation between sympatric forms appears to be less than that between neighbouring populations of the same form, judging from an examination of allele frequencies and/or allele compositions. There was extensive assortative mating by form between sockeye and kokanee, which was not totally accounted for by the large size difference. In the two systems examined, males preferred to mate with females of their own form. In sockeye, such preferences are expected because of the size difference between forms. In kokanee, such preferences are not expected based on size alone, suggesting the evolution of premating isolating mechanisms. The degree of premating isolation was positively correlated with the extent of genetic divergence between sympatric forms. The results of this study are related to existing models of sympatric speciation to hypothesize that sockeye and kokanee have diverged in sympatry. The probable differences in selection between the marine and freshwater environments coupled with the assortative mating resulting from their size difference may have caused subsequent genetic divergence. This divergence appears to have been followed by the evolution of premating isolation. / Science, Faculty of / Zoology, Department of / Graduate

This study examines the reproductive and population biology of a long-lived (80-y life span) fish, Sebastes alutus (Gilbert). The objectives of the study were (i) to establish whether groups of adult S. alutus delineated by exploitation histories could be objectively identified as separate sub-populations; (ii) to identify the effects of density-independent mortality caused by exploitation, and relate them to predictions of life history theory (iii) to examine the long-term implications of this mortality pressure on the dynamics of the species; and (iv) to determine the contribution of these results to the development of management programs for this species. A lernaepodid copepod gill parasite (Neobrachiella robusta (Wilson 1912)) was used for the first time as a biological tag to delineate separate sub-populations (stocks) of a commercial fish. Intensity of infection and mean characteristics of the parasite population per fish achieved complete separation between stocks indistinguishable with morphological features. Discriminant analysis showed the parasite also functioned moderately well (34-76% correct classification) as a stock discriminator of individual fish. Use of auxilliary information on the stock identity of hosts improved the classification power of the discriminant function. The density-independent mortality of the commercial fishery on S. alutus has severely truncated the age spectrum of some stocks. Some compensatory growth changes for fish in the stocks under the strongest selection are evident. Examination of the variance structure of female length at age suggests an inverse relation of mortality and growth rate giving rise to smaller, older fish. Smaller, older fish can be accounted for using the same growth function as for the larger fish seen at younger ages, and these similar growth forms can give an aggregate appearance of quadratic growth. Growth changes do not yield significant differences in size at maturity, although age at maturity changes, implying developmental or environmental constraints on maturation. Fecundity estimation methodology was evaluated and the volumetric method previously used for this species found to be inferior to a gravimetric method. Significant differences in fecundity as a function of body variables were found among exploitation groups. Significant differences in oocyte characteristics among stocks were found, with size and age shown to have separable effects. Lightly exploited stocks had significantly higher oocyte quality (as expressed in oocyte weight), effected through differences in the oocyte diameter-oocyte weight relationship. Histological examination details the developmental sequence of oocytes and establishes the maturation period of oocytes and fish. Northern stocks were shown to have significantly larger oocytes. Follicular atresia is suggested as an alternative energy source to the embryo death which has been presented as the source for matrotrophy in this genus. Complete atresia of a ripe oocyte complement was identified in this genus for the first time. No evidence of reproductive senescence was found. The hypothesis of increasing reproductive effort with age, including the independence of age and size effects, was confirmed. No evidence of reproductive cost could be found. The hypothesis of increased reproductive effort earlier in life as a mechanism to offset increased adult mortality was supported. However, the potential of this increase, achieved by growth rate increases, is much less than is needed to compensate for the reduction in lifetime reproductive effort caused by high fishing mortality. The effects of changing mortality rates on several reproductive value indices was examined with deterministic and stochastic simulation models. Cohort reproductive value is the most sensitive of the indices examined and may be the most robust to measurement error. Reproductive value is a more sensitive index of population state than other indices in use and may play a role in determination and evaluation of optimal harvest policies. However, an experimental approach to its use will be required. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 4 uppsatser.

While most human language is expressed verbally, the gestures produced concurrent to speech provide additional information, help listeners interpret meaning, and provide insight into the cognitive processes of the speaker. Several theories have suggested that gesture played an important, possibly central, role in the evolution of language. Great apes have been shown to use gestures flexibly in different situations and to modify their gestures in response to changing contexts. However, it has not previously been determined whether ape gestures are defined by structural variables, carry meaning, are used to intentionally communicate specific information to others, or can be used strategically to overcome miscommunication. To investigate these questions, I studied three captive populations of orangutans (Pongo pygmaeus and P. abelii) in European zoos for 10 months. Sixty-four different gestures, defined through similarities in structure and use, were included in the study after meeting strict criteria for intentional usage. More than half of the gesture types were found to coincide frequently with specific goals of signallers, and were accordingly identified as having meanings. Both structural and social variables were found to determine gesture meaning. The recipient’s gaze in both the present and the past, and the recipient’s apparent understanding of the signaller’s gestures, affected the strategies orangutans employed in their attempts to communicate when confronted with different types of communicative failure (e.g. not seeing, ignoring, misunderstanding, or rejecting a gesture). Maternal influence affected the object-directed behaviour and gestures of infants, who shared more gestures with their mothers than with other females. These findings demonstrate that gesture can be used as a medium to investigate not only the communication but also the cognition of great apes, and indicate that orangutans are more sensitive to the perceptions and knowledge states of others than previously thought.

Após o parto, a mãe deve optar por buscar por comida ou cuidar da prole sendo que a substância cinzenta periaquedutal (PAG) é uma área central importante de regulação, seleção e um sítio de ação de opióides. Ainda não se sabe a importância funcional de cada um dos receptores opióides na PAG sobre a expressão dos comportamentos materno e predatório. Foram utilizadas ratas com cânula unilateral implantada na PAG e divididas em dois experimentos: Experimento 1, onde as ratas receberam injeções de agonista m, ou o agonista k, ou sulfato de morfina, ou veículo; Experimento 2, onde receberam antagonista m seguido de sulfato de morfina, ou antagonista k seguido de sulfato de morfina, ou sulfato de morfina, ou veículo. Os animais foram avaliados no teste de comportamento materno versus predatório. Os resultados sugerem que o tônus opióide endógeno é importante para a expressão do comportamento predatório e há possibilidade da morfina agir em mais de um tipo de receptor opióide simultaneamente para promover a inibição do comportamento materno nesse contexto. / After giving birth, a mother must both provide subsistence and care for her young. Periaqueductal gray (PAG) is an important area for behavioral selection and a site of opioid action. The functional role of PAG opioid receptors in the expression of maternal and predatory behaviors is not clear. Rats with unilateral guide cannulae implanted in the PAG were separated into two experiments: Experiment 1 where the animals received injectios of m receptor agonist, or k receptor agonist, or morphine sulfate, or vehicle; Experiment 2, where they received m receptor antagonist followed by morphine sulfate, or k receptor antagonist before morphine sulfate, or morphine sulfate, or vehicle. The animals were then tested for maternal behavior vs. predatory hunting. The results suggest that endogenous opioid tone is important for the expression of predatory behavior. The results further raise the possibility that morphine acts at more than one type of opioid receptor simultaneously to inhibit maternal behavior in this context.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 5 uppsatser.

Após o parto, a mãe deve optar por buscar por comida ou cuidar da prole sendo que a substância cinzenta periaquedutal (PAG) é uma área central importante de regulação, seleção e um sítio de ação de opióides. Ainda não se sabe a importância funcional de cada um dos receptores opióides na PAG sobre a expressão dos comportamentos materno e predatório. Foram utilizadas ratas com cânula unilateral implantada na PAG e divididas em dois experimentos: Experimento 1, onde as ratas receberam injeções de agonista m, ou o agonista k, ou sulfato de morfina, ou veículo; Experimento 2, onde receberam antagonista m seguido de sulfato de morfina, ou antagonista k seguido de sulfato de morfina, ou sulfato de morfina, ou veículo. Os animais foram avaliados no teste de comportamento materno versus predatório. Os resultados sugerem que o tônus opióide endógeno é importante para a expressão do comportamento predatório e há possibilidade da morfina agir em mais de um tipo de receptor opióide simultaneamente para promover a inibição do comportamento materno nesse contexto. / After giving birth, a mother must both provide subsistence and care for her young. Periaqueductal gray (PAG) is an important area for behavioral selection and a site of opioid action. The functional role of PAG opioid receptors in the expression of maternal and predatory behaviors is not clear. Rats with unilateral guide cannulae implanted in the PAG were separated into two experiments: Experiment 1 where the animals received injectios of m receptor agonist, or k receptor agonist, or morphine sulfate, or vehicle; Experiment 2, where they received m receptor antagonist followed by morphine sulfate, or k receptor antagonist before morphine sulfate, or morphine sulfate, or vehicle. The animals were then tested for maternal behavior vs. predatory hunting. The results suggest that endogenous opioid tone is important for the expression of predatory behavior. The results further raise the possibility that morphine acts at more than one type of opioid receptor simultaneously to inhibit maternal behavior in this context.