Influence of the baroreceptor reflex on the modulation of @entity1063 overflow through prejunctional receptors in the portal vein of freely moving XXXX .

@entity7284 @entity1854 @entity1808 @entity551 @entity2647 @entity35 @entity1063
1. The effects of alterations in @entity551 ( @entity551 ), as induced by vasoactive drugs, on heart rate (HR), basal @entity1063 concentration and electrically evoked @entity1063 overflow and on blood flow in the portal vein of freely moving @entity35 , were investigated. 2. By infusion of @entity1854 or @entity2647 (0.5, 1.0 and 2.5 micrograms kg-1 min-1), @entity551 was altered over a range of 50 to 150 mmHg. The resulting changes in HR showed a sigmoidal relationship with @entity551 . @entity1063 overflow increased linearly when @entity551 was decreased; when @entity551 was increased, however, @entity1063 levels only decreased to 70% and reached a plateau from 125 mmHg onwards. 3. @entity1854 (2.5 micrograms kg-1 min-1) and @entity7284 (0.25 mg kg-1) decreased @entity551 to the same extent (-46 mmHg). HR and basal @entity1063 concentration, however, were increased to a higher extent by @entity7284 (+192 beats min-1; +373 pg ml-1, respectively) than by @entity1854 (+78 beats min-1; +206 pg ml-1, respectively). Electrically evoked overflow was not changed at all after @entity1854 , whereas @entity7284 induced an increase to 206% of control. 4. @entity2647 (2.5 micrograms kg-1 min-1) and @entity1808 ) increased @entity551 to the same extent (to 155 and 161 mmHg, respectively). Basal @entity1063 concentration decreased by 30% after @entity2647 , whereas @entity1808 increased @entity1063 levels to 226% of control. Evoked @entity1063 overflow was not changed after @entity2647 but was increased to 204% of control after @entity1808 .(ABSTRACT TRUNCATED AT 250 WORDS)
