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Objective: We speculated that subarachnoid hemorrhage (SAH) induces ischemic lesions in the cranial parasympathetic nerves, which may decrease saliva secretion and lead to hyperthermia. We tested this hypothesis by examining histologic features of parotid glands and glossopharyngeal nerves (GPNs) in a rabbit model of SAH.
Material and Methods: Rabbits (n = 25) were divided into control (n = 5), sham (n = 5), and SAH (n = 15) groups. Animals in the sham and SAH groups were examined over a 3-week period before sacrifice. Salivation score (SC) was determined by measuring the mean wetted area of an orally inserted cotton ball. Sections of parotid glands and intracranial and intraparotideal branches of the GPNs were stained with hematoxylin and eosin and SAH-induced damage was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling of apoptotic cells. Specimens were stereologically examined to determine saliva-filled total vesicle volume (TVV) per cubic meter; vasospasm index (VSI) based on wall/lumen ratio of parotid glands arteries, and degenerated neuron density (DND) of glossopharyngeal ganglia.
Results: The mean oral temperature was 36.9°C. In the control group, mean values were as follows: SC, 46±8 mm2; DND, 19±4/mm3; VSI, 1.065±0.049; and TVV, (780±1187) × 106/µm3. In the sham group, mean values were as follows: SC, 31±6 mm2; DND, 98±23/mm3; VSI, 1.67±0.32; and TVV, (617±110) × 106/µm3. In the low hyperthermia SAH group, mean values were as follows: SC, 16±5 mm2; DND, 1520±261/mm3; VSI, 2.12±0.21, and TVV, (314±98) × 106/µm3. In the high hypothermia SAH group, mean values were as follows: SC, 9±2 mm2; DND, 3210±912/mm3; VSI, 3.18±0.30; and TVV, (432±99) × 106/µm3.
Conclusions: Decreased salivary secretion due to secretory gland atrophy originated from ischemia-induced GPN network degeneration at the brainstem, which may be responsible for cranial hyperthermia following SAH.
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2. Zhang G, Zhang JH, Qin X: Effect of weekend admission on in-hospital mortality after subarachnoid hemorrhage in Chongqing China. Acta Neurochir Suppl 110:229–232, 2011
3. Scaravilli V, Tinchero G, Citerio G: Participants in the International Multi-Disciplinary Consensus Conference on the Critical Care Management of Subarachnoid Hemorrhage. Neurocrit Care 15:287–294, 2011
4. Emmelin N: Nerve interactions in salivary glands. J Dent Res 66:509–517, 1987
5. Rezek O, Boldogkoi Z, Tombácz D, Kovágó C, Gerendai I, Palkovits M, Tóth IE: Location of parotid preganglionic neurons in the inferior salivatory nucleus and their relation to the superior salivatory nucleus of rat. Neurosci Lett 8:440:265–269, 2008
6. Takahashi H, Izumi H, Karita K: Parasympathetic reflex salivary secretion in the cat parotid gland. Jpn J Physiol 45(3):475–490, 1995
7. Baum BJ: Principles of saliva secretion. Ann NY Acad Sci 694: 17–23, 1993
8. Kim M, Chiego DJ Jr, Bradley RM: Morphology of parasympathetic neurons innervating rat lingual salivary glands. Auton Neurosci 31:111(1):27–36, 2004
9. Mink S, Schwarz U, Mudra R: Treatment of resistant fever: new method of local cerebral cooling. Neurocrit Care 15:107–112, 2011
10. Todd MM, Hindman BJ. Clarke WR, Torner JC, Weeks JB, Bayman EO, Shi Q, Spofford CM: Perioperative fever and outcome in surgical patients with aneurysmal subarachnoid hemorrhage. Neurosurgery 64:897–908, 2009
11. Naidech AM, Bendok BR, Bernstein RA, Alberts MJ, Batjer HH, Watts CM, Bleck TP: Fever burden and functional recovery after subarachnoid hemorrhage. Neurosurgery 63:212–217, 2008
12. Shahlaie K, Keachie K, Hutchins IM, Rudisill N, Madden LK, Smith KA, Ko KA, Latchaw RE, Muizelaar JP: Risk factors for posttraumatic vasospasm. J Neurosurg 115:602–611, 2011
13. Tekdemir I, Aslan A, Tüccar E, Cubuk HE, Elhan A, Deda H: An anatomical study of the tympanic branch of the glossopharyngeal nerve (nerve of Jacobson). Ann Anat 180:349–352, 1998
14. Garrett JR, Proctor GB: Control of salivation; in Linden RWA (ed): The Scientific Basis of Eating. Taste, Smell, Mastication, Salivation, and Swallowing and Their Dysfunctions. Front Oral Biol. Basel, Karger, 135–155, 1998
15. Matsuo R, Yamamoto T, Kiyomitsu Y, Morimoto T: Neural substrates for reflex salivation induced by taste, mechanical, and thermal stimulation of the oral region in decerebrate rats. Jpn J Physiol 39:349–357, 1989
16. Simon E, Mertens P: Functional anatomy of the glossopharyngeal, vagus, accessory and hypoglossal cranial nerves. Neurochirurgie 55:132–135, 2009
17. Miyake Y: Chorda versus glossopharyngeal nerve in the reflex parotid secretion]. Nihon Seirigaku Zassh 31:268–276, 1969
18. Schneyer CA, Hall HD: Amylase and electrolyte changes after postganglionic parasympathectomy of parotid gland. Am J Physiol 207:308–312, 1964
19. Edwards AV, Titchen DA: The effect of parasympathetic postganglionic denervation on parotid salivary protein secretion in anaesthetized sheep. Auton Neurosci 30:100(1-2):50–57, 2002
20. Hamosh M: Rat lingual lipase: factors affecting enzyme activity and secretion. Am J Physiol 235(4): 16–21, 1978
21. Patterson J, Lloyd LC, Titchen DA: Secretory and structural changes in the parotid salivary gland of sheep and lambs after parasympathetic denervation. Q J Exp Physiol 60: 223– 232, 1975.