Integration of Chemosensory and Hormonal Stimuli

描述(申请人提供)：性腺类固醇激素是雄性仓鼠交配所必需的，就像大多数哺乳动物一样。阉割也会降低性动机，这是通过对阴道气味的兴趣和对接受能力强的女性的偏好来衡量的。然而，对类固醇刺激食欲性行为的机制的了解是有限的。这是拟议研究的总体目标。仓鼠是研究性动机的重要模型，因为交配依赖于化学感觉线索。雄性仓鼠在交配前对雌性仓鼠进行广泛的肛门生殖调查，移除嗅球会取消交配和对发情雌性仓鼠的偏好。具体目标1的研究将调查去势和类固醇替代对雌性仓鼠阴道分泌物(FHV)检测和反应性的影响，以确定被去势的雄性是否能够检测到FHV，以及传递对FHV反应性的类固醇信号。条件性味觉回避将用于评估化学感觉检测(目标1A)，而目标1B和1C将使用操纵剂对FHV的反应来评估化学感觉反应。特定目标2将确定荷尔蒙控制化学感觉反应的大脑路径。Aim 2A将研究有益的化学感觉线索在嗅黏膜和/或犁鼻器官中的转导。目标2B和2C将集中在嗅球的中央靶点。内侧视前区(MPOA)是表达完全性行为的关键。然而，MPOA的损伤并不能阻止对发情期女性的偏好，这表明大脑的其他区域有助于类固醇对性动机的影响。杏仁内侧核(Me)在这方面是一个合乎逻辑的部位。我从嗅球接受传出，并有丰富的类固醇受体。我们已经证明，我体内的睾丸激素刺激了被阉割的男性的性行为。AIMS 2B和2C将使用损伤和激素刺激来确定Me和MPOA在类固醇促进化学感觉反应中的作用。这些研究对于理解性动机以及类固醇激素在性欲行为中的意义具有重要意义。

DESCRIPTION (provided by applicant): Gonadal steroid hormones are essential for mating in male hamsters, as in most mammals. Castration also reduces sexual motivation, as measured by interest in vaginal odors and preference for a receptive female. However, understanding of mechanisms for steroid stimulation of appetitive sexual behavior is limited. This is the overall objective of the proposed studies. Hamsters are an important model for investigating sexual motivation because mating is dependent on chemosensory cues. Male hamsters engage in extensive anogenital investigation of females before mating, and removal of the olfactory bulbs abolishes both copulation and preference for an estrous female. Studies in Specific Aim 1 will investigate the effects of castration and steroid replacement on detection of and responsiveness to female hamster vaginal secretion (FHVS) to determine if castrated males can detect FHVS, and the steroid signals that convey responsiveness to FHVS. Conditioned taste avoidance will be used to assess chemosensory detection (Aim 1A), while Aims 1B and 1C will evaluate chemosensory responsiveness using operant responding for FHVS. Specific Aim 2 will determine brain pathways for hormonal control of chemosensory responsiveness. Aim 2A will investigate the transduction of rewarding chemosensory cues in the olfactory mucosa and/or vomeronasal organ. Aims 2B and 2C will focus on central targets of the olfactory bulbs. The medial preoptic area (MPOA) is key to expression of consummatory sexual behavior. However, lesions of MPOA fail to prevent preference for an estrous female, suggesting that other brain regions contribute to steroidal effects on sexual motivation. The medial amygdaloid nucleus (Me) is a logical site in this regard. Me receives efferents from the olfactory bulbs, and has abundant steroid receptors. We have shown that testosterone in Me stimulates sexual activity in castrated males. Aims 2B and 2C will use lesions and hormone stimulation to determine the role of Me and MPOA in steroid facilitation of chemosensory responsiveness. These studies have relevance to understanding sexual motivation, and the significance of steroid hormones in appetitive sexual behavior.