[Kinetic assessment of salivary secretory response to citric acid. Differences with pilocarpine].
BACKGROUND
Induction of salivation is becoming increasingly popular in the assessment of salivary gland status. Various mechanical or pharmacological procedures are empirically used to produce salivation. Oral stimulation by citric acid (AC) is by far the most used sialagogue procedure.


OBJECTIVE
To characterize the salivary secretory response to AC solutions applied to the dorsolateral tongue surfaces.


METHODS
Young healthy women from the upper levels of a medical career (n = 19) participated as volunteers. Salivary volume and UV-absorbing organic material in saliva from single subjects were measured after various protocols of topical stimulation by AC.


RESULTS
After a single stimulation by 1-8% AC the salivary flow rate peaked before 30 seconds and recovered the basal level earlier than 2 minutes. Repetitive stimulations at 30-sec intervals kept the flow rate at a maximum. After suspending these stimulations, basal flow rate was recovered before 2 minutes. Repetitive AC-stimulations at 8-min intervals produced a series of identical and independent secretory responses. The concentration of organic material in saliva remained unaltered after the various modes of stimulation. Thus, the profile of organic material secretion was always a direct expression of changes in salivary flow rate. In contrast to AC, the oral administration of the cholinergic agonist pilocarpine (PIL) produced a two-wave salivary response that as a whole lasted for about 30 minutes. In this case the volume and the amount of organic material were at least 10-fold the ones secreted in response to AC.


CONCLUSIONS
AC provoked a rapid and short-lived salivary response that differs markedly from the one produced by other secretagogues, like pilocarpine.
Durán
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Programa de Formación de Ayudantes Alumnos, Facultad de Medicina, Universidad de Chile.
Domínguez
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Morales
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López
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RO
D000328:Adult; D019343:Citric Acid / Q000494:pharmacology*; D005260:Female; D006801:Humans; D018721:Muscarinic Agonists / Q000494:pharmacology*; D010862:Pilocarpine / Q000494:pharmacology*; D012472:Salivation / Q000187:drug effects*; D013997:Time Factors
D018721:Muscarinic Agonists; D010862:Pilocarpine; D019343:Citric Acid