Salivary reflex

The simple or unconditioned salivary reflex occurs when food is present within the oral cavity and causes stimulation of chemoreceptors and pressure receptors. These receptors then transmit impulses to the salivary center in the medulla of the brainstem. Parasympathetic efferent impulses are transmitted back to the salivary glands and secretion is enhanced. 

The acquired or conditioned salivary reflex is elicited in response to the thought, sight, smell, or sound of food. As demonstrated with Pavlov s dog, these stimuli result in a learned response. Another stimulus that enhances salivation is nausea. Salivary secretion is inhibited by fatigue, sleep, fear, and dehydration. Overall, 1 to 2 1 of saliva may be produced per day. 

Due to parasympathetic stimulation of the salivary glands, saliva is secreted continuously at a basal rate of approximately 0.5 ml/min. Secretion may be enhanced by two types of reflexes ... 

Sradycard/a Atropine is used in the suppression of vagally mediated bradycardias. Preoperative medication Atropine, scopolamine, hyoscyamine, and glycopyrrolate are used as preanesthetic medication to control bronchial, nasal, pharyngeal, and salivary secretions and to block cardiac vagal inhibitory reflexes during induction of anesthesia and intubation. Scopolamine is used for preanesthetic sedation and for obstetric amnesia. 

Another characteristic of irritative stimulation of the trigeminal nerve is the defensive reflexes (e.g., sneezing) invoked by the body to remove or dilute the offending substance. In the case of oral chemical heat, the burning sensation from capsaicin invokes sweating, tearing, and copious salivation. Salivary flow... 

Substance P is an 11-amino-acid peptide amide hormone discovered by von Euler and Gaddum in 1931 (43) from certain tissue extracts, especially from intestinal plain muscles and brains of horses. It is involved in the transmission of pain impulses from peripheral receptors to the central nervous system. It is also involved in the vomit reflex, stimulates salivary secretions, and induces vasodilation. Antagonists seem to have antidepressant properties. 

Enflurane is indicated to provide analgesia for vaginal delivery, and in combination with other anesthetic agents, it is used for delivery by cesarean section. It does provide adequate muscular relaxation. Enflurane, an inhalation anesthetic, produces rapid induction and recovery. It obtunds pharyngeal and laryngeal reflexes and causes salivary... 

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