Autonomic stress

Beta-blocker—Drug that suppresses the autonomic stress response that causes fear-like symptoms brought on by social anxiety disorder. 

CRH (Corticotropin releasing hormone) is expressed in the nucleus paraventricularis of the hypothalamus and drives the stress hormone system by activating synthesis and release of corticotropin at the pituitary and in turn corticosteroid from the adrenal cortex. CRH is also expressed at many other brain locations not involved in neuroendocrine regulation, e.g. the prefrontal cortex and the amygdala. Preclinical studies have shown that CRH also coordinates the behavioral adaptation to stress (e.g. anxiety, loss of appetite, decreased sleepiness, autonomic changes, loss of libido). 

The locus cemleus is important for the regulation of attentional states and autonomic nervous system activity. It has also been implicated in the autonomic and stress-like effects of opiate withdrawal. A noradrenergic pathway originating from the locus cemleus which descends into the spinal cord is part of the descending inhibitory control system, which has an inhibitory effect on nociceptive transmission in the dorsal horn. 

Psychological stress may influence the immune system by activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary axis (SAM). The well-described innervation of primary and secondary lymphoid tissues by the autonomic nervous system also has been implicated in stress-related modulation of the immune response. These pathways operate by producing biological mediators that interact with and affect cellular components of the immune system.13... 

Figure 19.17 The biochemistiy and physiology responsible for penile erection. Sexual activity itself begins with a state of arousal that leads to erection. Arousal results in part from stimulation of the sense organs. The hypothalamus coordinates the sensations and activates the autonomic nervous system. Sensory nerves from the skin of the penis and other erogenous zones stimulate the parasympathetic system. This activates nitric oxide synthase and the resultant nitric oxide, via cyclic GMP, causes vasodilation of the arterioles. This increases blood flow through the corpora cavernosa which then expands producing an erection. Pheromones secreted by the female can stimulate the odour detecting system in the nasal cavity of the male (Chapter 12 and see above). Stress, however, activates the sympathetic system releases cyclic AMP which can result in vasoconstriction of the arterioles. Other factors that can interfere with an erection are physical fatigue and alcohol.

Finley JC, O Leary M, Wester D, MacKenzie S, Shepard N, Farrow S, Lockette W. A genetic polymorphism of the alpha2-adrenergic receptor increases autonomic responses to stress. J Appl Physiol 2004 96(6) 2231-9. 

Gray TS (1990) Amygdaloid CRF pathways role in autonomic, neuroendocrine, and behavioral responses ot stress. In De Souza EB, Nemeroff CB (eds) Annals of the New York Academy of Sciences. Corticotropin-releasing factor and cytokines Proceedings of the Hans Selye Symposium on Nemoendocrinology and Stress, vol 697. New York Academy of Sciences, New York, pp 53-60... 

Walther DJ, Peter JU, Bashammakh S, Hortnagl H, Voits M, Fink H, Bader M (2003) Synthesis of serotonin by a second tryptophan hydroxylase isoform. Science 299 76 Wang X, Su H, Copenhagen LD, Vaishnav S, Fieri F, Shope CD, Brownell WE, De Biasi M, Paylor R, Bradley A (2002) Urocortin-deficient mice display normal stress-induced anxiety behavior and autonomic control but an impaired acoustic startle response. Mol Cell Biol 22 6605-6610... 

Heim C, Newport JJ, Heit S, Graham YP, Wilcox M, Bonsall R, Miller AH, Nemeroff CG (2000) Pituitary-adrenal and autonomic responses to stress in women after sexual and physical abuse in childhood. JAMA 284 592-597... 

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