Sexual function modulators

Figure 4 Selective nonpeptide modulators of melanocortin receptor subtypes. The MC4 R selective compound seems to affect sexual function, and the MCI R selective compound possess anti-inflammatory activity.

Other neurotransmitter systems, as well as various hormones, have been shown to modulate sexual function among these are progesterone and prolactin (which inhibit centrally mediated arousal) and testosterone (which stimulates centrally mediated arousal). 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

Blount, J. D., Metcalfe, N. B., Birkhead, T. R., and Surai, P. F. 2003. Carotenoid modulation of immune function and sexual attractiveness in zebra finches. Science 300 125-127. 

Another approach considers the effects of various ligands on their receptors located in the diencephalic and mesiotemporal areas. Cell clusters in the hypothalamus coordinate the normal regulation of the vegetative functions of sleep, appetite, and sexual drive, which are typically disrupted in severe depression. In addition, the limbic area modulates many aspects of behavior and mood that are characteristically disturbed in affective disorders. 

Monti-Block et al. (1994) [268] found that the adult human VNO is a functional chemosensory organ with a sexually dimorphic specificity to patented chemical stimuli called "vomeropherins" which seem to fit the definition of pheromones. The adult human VNO also appears to have the ability to transduce social-environmental chemical signals, which modulate certain autonomic functions (e.g., electrodermal activity and body temperature). 

Alterations in 5-hydroxytryptamine (5-HT) neurotransmission have been implicated in a number of human disorders such as migraine, depression and anxiety as well as in normal human functions such as sleep, sexual activity and appetite. Unfortunately, the scientific association between 5-HT and these disorders has been largely suggestive rather than definitive. Nonetheless, recent advances in the understanding of 5-HT receptor subtypes have strengthened the ability to document specific links between modulation of 5-HT neurotransmission and human disease states. This brief chapter will present an overview of the current status of 5-HT receptor subtypes. 

There are three general mechanisms by which responsiveness to pheromones could be coordinated with reproductive maturity 1) reproductive hormones might directly affect primary receptor structure or function, 2) olfactory bulb activity could be modulated by efferent, hormone-sensitive fibres from the brain, and 3) the occurrence of appropriate behaviors could be influenced by hormone-dependent changes in sexual motivation. 

Steroids are hormones that are known to modulate DNA expression and protein expression. Adrenal hormones (e.g., aldosterone and cortisol) participate in the control of metabolism and of salt and water homeostasis. The other class of steroid hormones, gonadal hormones (e.g., estradiol, progesterone, and testosterone), influence mammalian sexual development and function. Several steroids also modulate neurotransmitter action, and some athletes have misused anabolic steroids to enhance their physical strength and performance. GC/MS has been used in conjunction with El or Cl as an ionization method for steroids to determine molecular mass, elemental composition, and length of the side chain of a steroid hydrocarbon. Although these techniques are highly sensitive, they require multistep derivatization of these thermally labile compounds. FAB-MS has proven to be a useful technique to analyze underivatized urinary... 

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