Gastrointestinal system stimulants

Gastrointestinal System. Stimulation of the gastrointestinal tract via parasympathetic cholinergic... 

Gastrointestinal effects can be caused by central nervous system stimulation (nausea) or by direct contact (necrosis) with cyanide salts. 

Action on the CNS depends directly on the dose of administered drug, and can be manifested as fatigue, anxiety, tremors, and even convulsions in relatively high doses. Theophylline acts on the cardiovascular system by displaying positive ionotropic and chronotropic effects on the heart, which, can likely be linked to the elevated influx of calcium ions by modulated cyclic adenosine monophosphate and its action on specific cardiac phosphodiesterases. In the gastrointestinal system, methylxanthines simultaneously stimulate secretion of both gastric juice and digestive enzymes. 

Actions Carbachol has profound effects on both the cardiovascular system and the gastrointestinal system because of its ganglion-stimulating activity and may first stimulate and then depress these systems. It can cause release of epinephrine from the adrenal medulla by its nicotinic action. Locally instilled into the eye, it mimics the effects of acetylcholine, causing miosis. 

The most striking effect of systemic absorption of cocaine is central nervous system stimulation. Signs and symptoms can include excitement, restlessness, rapid and irregular pulse, dilated pupils, headache, gastrointestinal upset, delirium, and convulsions. Death usually results from respiratory feilure. Moderate doses of cocaine can also raise body temperature. Systemic absorption through mucous membranes is rapid and has been compared in speed with that of intravenous administration. 

Toxic effects are an extension of terbutaline s pharmacologic activity. Common symptoms include hypertension, tachycardia, arrhythmias, central nervous system stimulation, gastrointestinal effects, and transient electrolyte changes (e.g., hypokalemia). 

Psychoactive plants have been used by humans for recreational, spiritual, and therapeutic purposes for millennia (6). It is evident from the African plants that have received the most attention, such as T. iboga and Catha edulis that research has been focused on those plants most commonly used for spiritual or recreational purposes. This is understandable as these plants are often more obvious because of their cultural importance and consequently more noticeable, in particular hallucinogens. The more subtle, often more therapeutically important plants, such as mild stimulants, sedatives, those used to treat convulsions and epilepsy have been sadly overlooked. The CNS-related mode of action of many plants may not immediately be obvious, for example nausea and vomiting are associated with the gastrointestinal system but is often treated via the CNS with scopolamine. The hunger-suppressant (anorectic) activities of South African succulent plants of the species Hoodia (7) are another example. 

Rbi, a representative of the saponins derived from 20(S)-proto-panaxadiol (26) (Table I) reportedly exhibited central nervous system-depressant and antipsychotic activity, protection of stress ulcer, increase of gastrointestinal motility and weak anti-inflammatory action, while Rgi, the major saponin of 20( S)-protopanaxatriol (36) (Table II) showed weak central nervous system-stimulant action, antifatigue action and aggravation of stress ulcer (757, 752, 755, 164, 165, 166). Kaku etal. 167) on investigating the pharmacology of the major saponins, reported the... 

Stimulation of the parasympathetic system induces increased gastrointestinal activity. Generally, the parasympathetic system is stimulatory to the gastrointestinal system during restand normal activity. 

Cortical stimulator and sensor, using battery-powered BION system, 34-15-34-16 Cough CPR, 18-7 Coupled nonlinear oscillators, in gastrointestinal system,... 

Resting potential, in membrane model, 22-2-22-3 Reswick, J., VII-2 Reticular lamina, 5-5 Retina, 4-2-4-3 Retinal ganglion cells, 22-12 Retinal horizontal cells, 22-12 Retinal stimulation, 35-2 Retinitis pigmentosa, sec RP Reul, H 44-3,55-5,55 12 Reynolds, D.V., 29-10 Rho,J.Y.,47-9 Rhode, W.S., 5-4,63-9 Rhythmic electrical activity, in gastrointestinal system, 6-6... 

The Class I agents have many similar side effects and toxicities. The anticholinergic side effects include dry mouth, constipation, and urinary hesitancy and retention. Common gastrointestinal (GI) side effects include nausea, vomiting, diarrhea, and anorexia. Cardiovascular adverse effects are hypotension, tachycardia, arrhythmias, and myocardial depression, especially in patients with congestive heart failure. Common central nervous system (CNS) side effects are headache, dizziness, mental confusion, hallucinations, CNS stimulation, paraesthesias, and convulsions. 

As to be expected from a peptide that has been highly conserved during evolution, NPY has many effects, e.g. in the central and peripheral nervous system, in the cardiovascular, metabolic and reproductive system. Central effects include a potent stimulation of food intake and appetite control [2], anxiolytic effects, anti-seizure activity and various forms of neuroendocrine modulation. In the central and peripheral nervous system NPY receptors (mostly Y2 subtype) mediate prejunctional inhibition of neurotransmitter release. In the periphery NPY is a potent direct vasoconstrictor, and it potentiates vasoconstriction by other agents (mostly via Yi receptors) despite reductions of renal blood flow, NPY enhances diuresis and natriuresis. NPY can inhibit pancreatic insulin release and inhibit lipolysis in adipocytes. It also can regulate gut motility and gastrointestinal and renal epithelial secretion. 

Pituitary Adenylyl Cyclase-activating Polypeptide (PACAP) is a 38-amino acid peptide (PACAP-38), which is widely expressed in the central nervous system. PACAP is most abundant in the hypothalamus. It is also found in the gastrointestinal tract, the adrenal gland and in testis. Its central nervous system functions are ill-defined. In the periphery, PACAP has been shown to stimulate catecholamine secretion from the adrenal medulla and to regulate secretion from the pancreas. Three G-protein coupled receptors have been shown to respond to PACAP, PAQ (PACAP type I) specifically binds PACAP, VPACi and VPAC2 also bind vasoactive intestinal peptide (VDP). Activation of PACAP receptors results in a Gs-mediated activation of adenylyl cyclase. 

Clinical signs and symptoms of toxicity are related to the overstimulation of muscarinic, nicotinic, and central nervous system receptors in the nervous system. Muscarinic receptors are those activated by the alkaloid drug muscarine. These receptors are under the control of the parasympathetic nervous system, and their hyperactivity results in respiratory and gastrointestinal dysfunction, incontinence, salivation, bradycardia, miosis, and sweating. Nicotinic receptors are those activated by nicotine. Hyperactivity of these receptors results in muscle fasciculations even greater stimulation results in blockade and muscle paralysis (Lefkowitz et al. 1996 Tafliri and Roberts 1987). Hyperactivity of central nervous system receptors results in the frank neurological signs of confusion, ataxia, dizziness, incoordination, and slurred speech, which are manifestations of acute intoxication. Muscarine and nicotine are not... 

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