Biomedical subjects

A Barden

Publications and source records attributed to A Barden.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Effect of captopril on blood pressure and bradykinin vasodepressor responses after nephrectomy and suppression of prostaglandin synthesis in anaesthetized rats.

1. Captopril markedly potentiated the vasodepressor responses to bradykinin. Neither the magnitude nor duration of the blood pressure fall were altered by bilateral nephrectomy or treatment with indomethacin which suppressed urinary excretion of the prostacyclin metabolite 6-Keto- PGF1 alpha. 2. It is concluded that in the anaesthetized rat augmentation of the bradykinin depressor responses by captopril occurs independently of endogenous prostaglandin synthesis.

Anesthesia, General↗

PubMedDate not supplied

Role of prostaglandins during reversal of one-kidney, one-clip hypertension in the rat.

Unclipping the one-kidney, one-clip rat returned blood pressure to normotensive levels within 24 h and was associated with a substantial increase in urinary PGE2 and 6-keto PGF1 alpha excretion. Prior treatment with indomethacin (6.0 mg/kg) markedly reduced urinary prostaglandins after clip removal and attenuated the fall in blood pressure. Aspirin (100 mg/kg) treatment, which reduced 6-keto PGF1 alpha to a lesser degree without altering PGE2 excretion, had no significant effect on the blood pressure fall. It is suggested that in the one-kidney, one-clip rat prostaglandins are released as the result of exposing the unclipped kidney to elevated arterial pressure, and that these contribute to the subsequent fall in blood pressure.

Animals↗

PubMedDate not supplied

The measurement of plasma thromboxane B2 and the effect of smoking.

Plasma thromboxane B2 (TxB2) was measured by radioimmunoassay using an iodinated ligand following extraction and further purification by thin layer chromatography. Venous blood was sampled into a syringe containing the cyclooxygenase inhibitor meclofenamate. Normal levels, 15 pg/ml (s.d. = 8, n = 21), were lower than usually reported and measured values increased several fold over 20 min sampling from an indwelling needle. With appropriate sampling there was a statistically insignificant increase in plasma TxB2 after subjects smoked two cigarettes (n = 11). An average decrease occurred in a control group (n = 10) and the difference between groups was of borderline significance (P less than 0.05). Smoking did not change TxB2 production associated with platelet aggregation induced in vitro by collagen, whereas plasma adrenaline increased significantly. The results emphasize the importance of the technique of sampling and assay in the measurement of plasma TxB2.

Adult↗

PubMedDate not supplied

Increased renal prostanoid synthesis after unclipping the one-kidney, one-clip hypertensive rat: effect of renal denervation.

Renal denervation of hypertensive one-kidney, one-clip (1K, 1C) rats resulted in a minor fall in blood pressure (216, s.e.m. = 4, to 182, s.e.m. = 4, mmHg) 24 h later, which returned to predenervation levels with 1 week. Subsequent unclipping led to a similar fall in blood pressure in denervated (202, s.e.m. = 4 to 142, s.e.m. = 3) and sham-denervated (211, s.e.m. = 5 to 147, s.e.m. = 4) rats. Unclipping also resulted in a marked rise in urinary PGE2 and 6-keto PFG1 alpha in both denervated and sham-denervated animals. It appears that 1K, 1C hypertension, 8 weeks after clipping, is only slightly dependent on renal nerves. Unclipping results in increased renal synthesis of PGE2 and PGI2 which is not dependent on intact renal innervation.

Animals↗

PubMedDate not supplied

Potentiation of bradykinin by captopril during suppression of prostacyclin synthesis.

The effect of captopril on blood pressure and on the depressor responses to intravenously administered bradykinin was examined in anesthetized normotensive rats during inhibition of prostaglandin synthesis. The hypotensive action of captopril persisted after treatment with indomethacin in doses that markedly suppressed urinary excretion of the prostacyclin metabolite 6-keto prostaglandin F1 alpha. Captopril markedly potentiated the vasodepressor responses to intravenous bradykinin given by bolus injection or continuous infusion. Neither the magnitude nor the duration of the blood pressure fall were affected by treatment with indomethacin. It is concluded that in the anesthetized rat the hypotensive action of captopril and its augmentation of the depressor response to bradykinin is independent of prostacyclin synthesis.

6-Ketoprostaglandin F1 alpha↗