Involvement of the Central Nervous System in the Salivary Secretion Induced by Pilocarpine in Rats

Abstract

The effect of rats of an anteroventral third ventricle (AV3V) electrolytic lesion on salivary secretion induced by intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) injection of a cholinergic agonist (pilocarpine) was investigated. Sham- or AV3V-lesioned rats anesthetized with urethane and with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The amount of salivary secretion was studied over a seven-minute period after i.c.v. or i.p. injection of pilocarpine. In sham-operated rats, i.p. injection of pilocarpine (1 mg/kg b.w.) (after 6 h, 2, 7, and 15 days) produced salivary secretion (486 +/- 21, 778 +/- 85, 630 +/- 50, and 560 +/- 55 mg/7 min, respectively). This effect was reduced 6 h, 2, and 7 days after an AV3V lesion (142 +/- 22, 113 +/- 32, and 290 +/- 62 mg/7 min, respectively), but not 15 days after an AV3V lesion (516 +/- 19 mg/7 min). I.c.v. injection of pilocarpine (120 micrograms in 1 microL), in sham-operated rats after 6 h, 2, 7, and 15 days also produced salivary secretion (443 +/- 20, 417 +/- 81, 496 +/- 14, and 427 +/- 47 mg/7 min, respectively). The effects of i.c.v. pilocarpine were also reduced 6 h, 2, and 7 days after an AV3V lesion (143 +/- 19, 273 +/- 14, and 322 +/- 17 mg/7 min, respectively), but not after 15 days (450 +/- 28 mg/7 min). The results demonstrate that the central nervous system, and particularly the AV3V region, is important for the effect of pilocarpine on salivary secretion in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of nitric oxide of the median preoptic nucleus (MnPO) in the alterations of salivary flow, arterial pressure and heart rate induced by injection of pilocarpine into the MnPO and intraperitoneally

“…It has been demonstrated that pilocarpine, when injected intracerebroventricularly (icv), produced salivary secretion at a significantly higher level than control (11,16). It has also been reported that electrolytic lesion of the AV3V produced a decrease in salivary flow induced by pilocarpine injected icv (11). These results indicate that other areas of the CNS, such as the areas surrounding the third ventricle, are important for pilocarpine-induced salivary secretion.…”

“…Pilocarpine at a concentration of 40 µg produced a medium salivary flow, whereas the flow rate increased in a linear fashion up to 160 µg. It has been demonstrated that pilocarpine, when injected intracerebroventricularly (icv), produced salivary secretion at a significantly higher level than control (11,16). It has also been reported that electrolytic lesion of the AV3V produced a decrease in salivary flow induced by pilocarpine injected icv (11).…”

“…The involvement of hypothalamic areas in the control of salivary secretion in rats has been shown by several studies (7)(8)(9)(10). The anteroventral third ventricle (AV3V) region is important for the effect of pilocarpine on salivary secretion in rats (11). Morphological, morphometric and stereological changes of submandibular glands were observed after lesion of the AV3V and ventromedial nucleus of hypothalamus (12).…”

Importância Da Região Anteroventral Do Terceiro Ventrículo (Av3v) No Controle Cardiovascular E Do Equilíbrio Hidroeletrolítico

“…Esta mesma lesão também atenua o aumento da pressão arterial, ingestão de água, natriurese e caliurese induzida pela injeção intracerebroventricular (icv) de carbacol (agonista colinérgico) 4 e mesmo ativação colinérgica de diversas áreas prosencefálicas, como área septal medial (ASM), órgão subfornical (OSF), hipotálamo ventro-medial (HVM) e área preóptica lateral (APL) 22/25 , ou caudais como locus coeruleus 26 . A lesão aguda da região AV3V também reduz a salivação induzida pela pilocarpina (intraperitoneal ou icv), o que tem contribuído para suportar a sugestão de que parte do efeito sialogogo deste agonista colinérgico depende também de uma ação central do mesmo 27,28 . Embora a lesão da região AV3V prejudique respostas pressoras de diversas origens, os animais com lesão aguda da região AV3V podem apresentar um pequeno aumento da pressão arterial acompanhada de taquicardia nos primeiros dias após a lesão 21 .…”

Endocannabinoids mediate hyposalivation induced by inflammogens in the submandibular glands and hypothalamus

“…11,12 It was reported that pilocarpine, a muscarinic agonist, injected intracerebroventricularly (icv) induced salivary secretion by activating central autonomic efferent fibres. 13 Cannabis consumption has been associated with a reduction in salivary flow and may lead to oral problems like progressive dental caries, fungal infection, oral pain, and dysphagia. 14,15 The main psychoactive ingredient of Cannabis sativa, D9-tetrahydrocannabinol (THC), affects different physiological functions.…”