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A double-blind trial of dihydroergotamine (DHE) nasal spray compared with placebo was carried out in patients with cluster headache. Twenty-five patients were included in the trial. In three patients, all receiving DHE, the pain attacks ceased after five attacks. In the other 22 patients, 133 attacks were treated with placebo and 137 attacks with DHE nasal spray (dosage, 1 mg of DHE). The trial showed that the treatment given has no effect on the attack frequency or the duration of the single attack. However, the treatment had a significant effect on the intensity of the single attacks. It can be concluded that the trial should be repeated, using a larger dosage of DHE. This should be ethically justifiable, since none of the patients had any adverse reactions locally in the mucous membrane of the nose or systemically.

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SUMMARYWe have examined the effect of antihypertensive treatment on heart weight and on structural and functional characteristics of isolated mesenteric resistance vessels (internal diameter 170-220 fun) in spontaneously hypertensive rats (SHR) and in Wistar-Kyoto rats (WKY). The SHR and WKY were treated with hydralazine from the age of 4 weeks and were examined at ages 12 to 14 weeks and 23 to 27 weeks. Treated SHR had a mean blood pressure as much as 29% below that of control WKY, which in turn was 25 to 40% less than that of control SHR. In 12-to 14-week-old rats the heart to body weight ratio (which in control SHR was 13% greater than that of WKY) was unaffected by treatment. Thereafter, the heart to body weight ratio of treated SHR did not increase as much as usual. At both ages, the media thickness and contractile response of the resistance vessels of the SHR (which were, respectively, 37% and 30% greater than those of vessels of WKY) were unaffected by treatment. However, because treatment caused a small (8%) increase in the lumen diameter of the vessels of the SHR, treatment did cause small, but possibly physiologically important, decreases both in the media to lumen ratio (11 %) and in the pressure against which these vessels would have been able to contract (10%). Treatment had little effect on the pharmacological characteristics of vessels of either SHR or WKY. The results suggest that the increased heart weight, media thickness, and contractile response in mesenteric resistance vessels of SHR up to ages 23 to 27 weeks are due primarily to factors other than increased pressure.

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The overall transfer function of a photoplethysmograph (PPG) converting changes in intravascular volume to changes in recorder pen deflection was investigated. The specifications of the apparatus working as a red cell densitometer were assessed in vitro, and it was found that PPG output is a logarithmic function of red cell density roughly in accordance with the Lambert-Beer theorem. In an in vivo experiment it was found that PPG output is also a logarithmic function of digital intravascular volume as assessed by means of air plethysmography. It is suggested that the equation for this in vivo function is different because of a dual action of stasis, producing increases in both intravascular volume and haematocrit. Although the relative contributions of the two disparate phenomena are not assessed further, it is concluded that their joint action on PPG output can be described by a monologarithmic function. In the Appendix, sources of non-linearity in the electronics of PPG are pointed out and instructions for the use of an exponential amplifier which will linearize the overall transfer function are given.

Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured during waterloading and constant infusion of [131I]hippuran and [125I]iothalamate in 24 mild to moderate essential hypertensive patients before and after 3.5 months treatment with atenolol. Clearances of sodium and potassium were measured 2-3 hours post-dosing and renal vascular resistance (RVR) and filtration fraction (FF) were calculated. Measurement of clearance of lithium (CLi) and uric acid (Curic acid) was employed to investigate specifically proximal tubular function. Beta-blockade with atenolol produced a borderline significant decrement in RPF but no change in GFR, RVR and FF. There was a significant reduction in CLi, fractional proximal escape of sodium and water, Curic acid and an increase in absolute proximal reabsorption of sodium, indicating an inhibition of proximal tubular function. The distal tubular parameters exhibited changes tending to normalize excretion of sodium, but not water. Changes in RVR were inversely related to changes in CLi and Curic acid, suggesting unopposed alfa-adrenergic stimulation to be implicated in the renal counterregulation at a proximal tubular site following long-term administration of atenolol in essential hypertension.

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