Effects of microinjection of kainic acid into the nucleus tractus solitarius on fluid and NaCl absorption across the jejunum
| Autor: | Kazutaka Tanaka, Kiyoshi Hosokawa, Hiroshi Suwaki, Hironobu Morita, Hiroshi Hosomi |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Atropine
Male Kainic acid medicine.medical_specialty Microinjections Physiology Efferent Blood Pressure Sodium Chloride Rats Sprague-Dawley Jejunum chemistry.chemical_compound Body Water Heart Rate Internal medicine Solitary Nucleus medicine Animals Mesentery Microinjection Kainic Acid General Neuroscience Solitary nucleus Yohimbine respiratory system Small intestine Rats medicine.anatomical_structure Endocrinology Intestinal Absorption nervous system chemistry Neurology (clinical) circulatory and respiratory physiology medicine.drug |
| Zdroj: | Journal of the Autonomic Nervous System. 48:97-104 |
| ISSN: | 0165-1838 |
| DOI: | 10.1016/0165-1838(94)90025-6 |
| Popis: | Effects of bilateral chemical inactivation of the nucleus tractus solitarius (NTS) by microinjection of kainic acid (KA) on fluid and NaCl absorption across the jejunum were examined in anesthetized Sprague-Dawley rats. Jejunal fluid and NaCl absorption was measured in a jejunal loop before and after the microinjection of artificial cerebrospinal fluid (aCSF) or KA into the NTS. Net fluid and NaCl absorption was not altered by a microinjection of aCSF. However, net fluid (from 1.12 +/- 0.07 to 1.66 +/- 0.06 ml/30 min) and NaCl (Na+ from 164.5 +/- 10.1 to 243.3 +/- 7.1 muEq/30 min; and Cl- from 175.9 +/- 7.5 to 260.8 +/- 6.5 muEq/30 min) absorption was significantly increased by the chemical inactivation of the NTS. To examine the efferent mechanism of the increased net absorption induced by the NTS inactivation, mesenteric nerve activity (MNA) was measured before and after the inactivation of the NTS. MNA was significantly increased by 165.9 +/- 74.2% after the bilateral inactivation of the NTS. Furthermore, absorption experiments were conducted in rats with pretreatment of atropine (acetylcholine-antagonist) or yohimbine (specific alpha 2-antagonist). In atropine treated rats, net jejunal absorption was significantly increased by the inactivation of the NTS. However, the increase in net absorption induced by the inactivation of the NTS was completely abolished by pretreatment with yohimbine. These results suggest that the NTS has a tonic suppression on jejunal absorption through alpha 2-adrenergic mechanism. |
| Databáze: | OpenAIRE |
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