Autonomous pathway

Demiryurek AT, Demiryurek S. Cardiotoxicity of digitalis glycosides roles of autonomic pathways, autacoids and ion channels. Autcn Autacoid Pharmacol. 2005 25 35-52. 

Ferguson AV, Washburn DL. Angiotensin II a peptidergic neurotransmitter in central autonomic pathways. Prog Neurobiol 1998 54 169-192. 

Trimethaphan is an antagonist at nicotinic ganglionic synapses. The drug thus blocks transmission of information through autonomic pathways in a dose-dependent manner. 

We propose two alternative mechanistic models for the temporal regulation of cellular responses to DNA damage. We describe them as the integrative surveillance (IS) and the autonomous pathway (AP) models (Fig. 3). These two hypothetical models represent two opposing philosophical views, but they may not be mutually exclusive. 

Fig. 3. Alternative models for the temporal coordination of DNA damage responses. (A) The integrative surveillance (IS) model proposes that signals indicating levels of DNA damage and the progress of repair are integrated by a regulatory hub to either activate or inhibit cell-cycle checkpoints versus apoptosis. The temporal coordination of different biological outcomes is the result of deliberated decisions made by the regulatory hub. (B) The autonomous pathway (AP) model proposes that DNA...

High-doses of systemic botulinum block cholinergic and adrenergic release, producing tonic and poorly responsive pupils that are not dominated by either autonomic pathway. 

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. 

Major efferent projections of the hypothalamic orexin system comprise descending and ascending, dorsal and ventral pathways that terminate preferentially in aminergic, endocrine, and autonomic control centers in the hypothalamus, midbrain, brainstem, and spinal cord, as well as in limbic cortical and subcortical structures, including sqDtum, amygdala, thalamus,... 

The efferent pathways of the ANS consist of two neurons that transmit impulses from the CNS to the effector tissue. The preganglionic neuron originates in the CNS with its cell body in the lateral horn of the gray matter of the spinal cord or in the brainstem. The axon of this neuron travels to an autonomic ganglion located outside the CNS, where it synapses with a postganglionic neuron. This neuron innervates the effector tissue. 

Figure 9.1 The autonomic nervous system and its effector organs. The efferent pathways of this system consist of two neurons that transmit impulses from the CNS to the effector tissue, preganglionic neuron (solid line), and postganglionic neuron (dashed line). As illustrated, most tissues receive nervous input from both divisions of the ANS the sympathetic and the parasympathetic.

Figure 9.2 Autonomic nerve pathways. All preganglionic neurons release acetylcholine (Ach), which binds to nicotinic receptors (N) on the postganglionic neurons. All postganglionic neurons in the parasympathetic system and some sympathetic postganglionic neurons innervating sweat glands release Ach that binds to muscarinic (M) receptors on the cells of the effector tissue. The remaining postganglionic neurons of the sympathetic system release norepinephrine (NE), which binds to alpha (a) or beta (P) receptors on cells of the effector tissue. The cells of the adrenal medulla, which are modified postganglionic neurons in the sympathetic system, release epinephrine (EPI) and NE into the circulation.

The autonomic nervous system exerts the primary control on heart rate. Because the sympathetic and parasympathetic systems have antagonistic effects on the heart, heart rate at any given moment results from the balance or sum of their inputs. The SA node, which is the pacemaker of the heart that determines the rate of spontaneous depolarization, and the AV node are innervated by the sympathetic and parasympathetic systems. The specialized ventricular conduction pathway and ventricular muscle are innervated by the sympathetic system only. 

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... 

The autonomic nervous system is by definition that part of the nervous system that innervates smooth muscle, cardiac muscle and glands. It is thus a motor system. Perception arising from the viscera involves pathways similar to those arising from the body surface and skeletal muscle. Thus there are visceral afferent fibres that pass from the viscera to the central nervous system. Such impulses then ascend the spinal cord to the thalamus and are thence relayed to the post-central gyrus of the brain (or sensory cortex). Visceral reflex arcs use visceral afferent fibres to convey impulses to the cord, but the efferent limb of such a visceral reflex is the autonomic nervous system. Although visceral reflexes are under higher central control, it is usually impossible to bring them under the control of the will. 

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... 

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