Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Lisa Eckel, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Sept. 18, 2006). Document formatted into pages; contains ix, 89 pages. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisors: Christine L. Duvauchelle and Terrence J. Monks. Vita. Includes bibliographical references.

Both chronic psychosocial stress and chronic administration of corticosterone have been shown to alter serotonergic type 2A (5-HT2A) receptor activity. A non-invasive behavioural index of 5-HT2A receptor activity is the frequency of "wet dog shakes" (WDS) or serotonergic stereotypy. In addition to WDS, 5-HT2A receptors mediate effects on sexual behaviour in the rat, in particular, inhibition in the male and stimulation in the female. In the present series of experiments, the potential involvement of stress and corticosterone in the regulation of WDS and sexual behaviour in the male and female rat was investigated. In Experiments 1-4, chronic exposure to several different forms of psychosocial stress was found to facilitate female and inhibit male rat sexual behaviour while concurrently increasing the display of WDS in both sexes. In Experiment 5, nefazodone, an antidepressant with 5-HT2A antagonistic properties, blocked the effects of stress on WDS but not sexual behaviour in female rats. In Experiments 6-7, the corticosterone synthesis inhibitor, metyrapone, blocked the effects of stress on sexual proceptivity and WDS in female rats. Metyrapone blocked the effects of stress on WDS but not sexual behaviour in male rats. In Experiments 8-9, high doses of corticosterone administered chronically facilitated female and inhibited male rat sexual behaviour while concurrently increasing WDS in both sexes. In Experiments 10-11, the 5-HT2A antagonist ketanserin was found to completely attenuate the effects of corticosterone on sexual behaviour and WDS in both male and female rats. In Experiments 12-13, the acute administration of corticosterone was found to exert no effect on either sexual behaviour or WDS in male or female rats. The present results indicate that both chronic corticosterone treatment and exposure to chronic stress inhibit male and facilitate female sexual behaviour while concurrently increasing WDS behaviour. The stress-induced facilitation of WDS appears to be related to elevated corticosterone levels and is suggestive of increased 5-HT2A activity. Both corticosterone and stress exerted effects on sexual behaviour in the direction that would be predicted by increased 5-HT2A activity. While the effects of corticosterone on sexual behaviour appear to be mediated by 5-HT2A activity, the effects of stress on sexual behaviour do not appear to be related to either elevations in corticosterone levels or alterations in 5-HT2A activity. / Arts, Faculty of / Psychology, Department of / Graduate

Determination of the physiologic roles of serotonin (5-HT) has long been hampered by the lack of compounds specific for certain of the 5-HT receptor subtypes. The objective of this dissertation was to characterize vascular serotonin receptors in certain arteries and to develop functional assays for the putative 5-HT₁(A) and 5-HT₂ receptors in vascular tissue to test novel compounds. Although 5-HT₁(A) receptor involvement in the 5-HT contraction of the canine basilar artery was previously reported, the 8-OH-DPAT (5-HT₁(A) specific agonist) EC₅₀ values in the canine, rabbit, guinea pig, and bovine basilar arteries studies were not consistent with the presence of 5-HT₁(A) receptors. Studies examining the 5-HT₂ selective antagonist ketanserin, several novel aryltryptamines with a range of affinities, and enantiomers of spiroxatrine, in the 5-HT-contracted rat aorta showed a good correlation between the aorta affinities and the affinities of these compounds at the [³H] ketanserin binding site (defined as 5-HT₂) in the rat frontal cortex. Comparison of the affinities of several known and novel compounds in the rat aorta and the rabbit femoral artery to the [³H] ketanserin site affinities in the frontal cortices of both species showed that the rabbit femoral artery 5-HT₂-like receptor was similar but not identical to either the rat aorta or the CNS sites from either species. The rabbit aorta and the rat femoral artery were then examined to determine if the 5-HT₂ receptor heterogeneity was species or vascular bed specific. The results from all four vascular tissues showed that no two tissues had identical responses to the compounds studied. The rat aorta appeared unique in the lack of agonist activity of RU24969 and the non-competitive antagonism of 5-HT by methysergide, but correlated to the CNS site for the affinities of all compounds. The major finding of the dissertation was the definitive evidence for vascular 5-HT₂ receptor heterogeneity; this subtype was previously thought to be homogeneous. Development of more selective compounds for 5-HT receptor subtypes may lead to greater understanding of the physiological roles of serotonin.

The brain is inherently bisexual, differentiating during development so that in adulthood, males mount receptive females. Yet, vestiges of this bisexuality persist in adults, with heterotypical behaviors (females mounting and males being receptive) observed in some species. Consequently, differences in sexual behavior between the sexes, and between individuals of the same sex, are reflective of the predisposition and degree to which these behaviors are exhibited. How one behavior is facilitated and its complement simultaneously suppressed during a reproductive encounter suggests that behavioral expression is gated in some manner. Because male and female vertebrates typically display behavior characteristic of their own sex, simultaneous study of neural circuits gating homotypical and heterotypical behaviors in conventional animal models has received scant attention. The whiptail lizard species, Cnemidophorus uniparens, comprises individuals that are genetically and hormonally female, and that naturally display both types of behavior. Using High Pressure Liquid Chromatography (HPLC), immunocytochemistry, in situ hybridization, intracranial surgeries, as well as pharmacological and behavioral analyses, I report that serotonin levels, and signaling via distinct serotonergic receptors at behaviorally relevant brain nuclei might allow the system to switch between either behavioral repertoire. The use of the same molecule to mediate the reciprocal inhibition of complementary behavioral repertories within the same sex is evidence of a phenomenon of molecular parsimony underlying a striking form of behavioral plasticity. This dissertation also illustrates that sexually differentiated traits such as male and female-typical sexual behaviors are sculpted by neurochemical signaling at neural substrates present in both sexes. / text

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Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

The present study ln male Wistar rats was designed to rate and analyze six specific cocaine-induced behaviors. These behavioral parameters have been defined by others as either dopaminergic (sniffing, grooming, and locomotor activity) or serotonergic (repetitive head movements, rearing, and Straub tail) in origin. Results were analyzed by analysis of variance in two ways : (i) as grouped dopaminergic or serotonergic scores, and (ii) as the net behavioral index (dopaminergic scores minus the serotonergic scores). The purpose of approaching the data in this way was to attempt to define the behavioral interactions of the two neurotransmitters. One conclusion that developed from this study was the indication that dopaminergic behaviors peak at lower doses of cocaine than do serotonergic behaviors. This relationship held true for all the individual parameters in addition to the dopaminergic and serotonergic totals. A dopaminergic blocker, haloperidol, significantly attenuated all responses elicited by cocaine. When the net behavioral index was analyzed, it was found that the response of the median dose of cocaine was significantly altered from a net dopaminergic score towards a net serotonergic score. In this sense, haloperidol was shown to have the capacity to attenuate dopaminergic-associated parameters to a greater extent than the serotonergic-associated parameters. Cyproheptadine, an antiserotonergic agent, did not significantly affect the net behavioral index; however, this compound did significantly increase the dopaminergic parameter of grooming at the high doses of cocaine and cyproheptadine. Also at this dose combination , gnawing was elicited -- a dopaminergic response seen under no other experimental conditions. Due to the antiserotonergic agent causing an increase in the dopaminergic parameters of grooming and gnawing, it is proposed that the serotonergic influence on these two dopaminergic behaviors is of an inhibitory type.

The mammalian serotonin system modulates a wide variety of emotional behaviors and states, including reward processing, anxiety, and social interaction. To reveal the underlying patterns of neural activity, we visualized serotonergic neurons in the dorsal raphe nucleus (DRN5-HT) of mice using miniaturized microscopy and calcium imaging during diverse emotional behaviors. In total, we imaged the activity of over 2,000 genetically-identified serotonin neurons. We discovered discrete ensembles of cells with highly correlated activity and found that DRN5-HT neurons are preferentially recruited by emotionally salient stimuli as opposed to neutral stimuli. Individual DRN5-HT neurons responded to diverse combinations of salient stimuli, with some preference for valence and sensory modality. Anatomically-defined subpopulations projecting to either a reward-related structure, the ventral tegmental area, or an anxiety-related structure, the bed nucleus of the stria terminalis, contained all response types, but were enriched in reward- and anxiety-responsive cells, respectively. Our results suggest that the DRN serotonin system responds to emotional salience using correlated ensembles with mixed selectivity and biases in downstream connectivity.