Is vasoactive intestinal polypeptide the principal transmitter involved in human penile erection?

Previous work from this laboratory reported on the effects of several autacoids and other agents on strips of human corpus cavernosum (cc) muscle. These investigations indicated the presence in the cc muscle of a) atropine-sensitive cholinoceptors, b) alpha- and beta-adrenoceptors and c) a non-adrenergic non-cholinergic mechanism. Several recent publications have presented evidence in support of the possibility that vasoactive intestinal polypeptide (VIP) is an important, or the chief, transmitter in human penile erection. This paper describes the actions of VIP and other compounds on the cc muscle and the effect of intracavernous injection of VIP in volunteers. Among the agents tested, VIP was the most potent relaxant of the cc muscle. This effect, which was seen at a dose as low as 0.03 nM, was suppressed by VIP antiserum. The response of the isolated penile vasculature to VIP was similar. VIP antiserum had no effect on the relaxation of the cc muscle produced by field stimulation. In five of the seven subjects given intracavernous VIP (1.0 micrograms.) some degree of penile enlargement was evident, but none had an erection. It is suggested that local release of VIP, withdrawal of the alpha-adrenoceptor mediated tonic supply to the penis and the activation of the latter's beta-adrenoceptors are all probably involved in penile erection in man.     

Bronchial venous plexus and its communication with pulmonary circulation

This study was undertaken to clarify the microvascular anatomy of the normal human bronchial circulation, focusing on the bronchial venous system and its communication with the pulmonary circulation. Ten normal lungs obtained at autopsy were studied. Bronchial arteriography was performed in six lungs, pulmonary arteriography in two lungs, and pulmonary venography in another two. Using radiologic methods, including microradiography, and serial histologic sections, we found numerous bronchial venous plexuses around the airways and blood vessels into which the bronchial capillaries drained. Frequent communications of the venous plexuses with the pulmonary veins and neighboring alveolar capillaries were also demonstrated. The bronchial venous plexus and its close connection with the pulmonary circulation may be important in various pathologic conditions involving the interstitial space, such as interstitial pulmonary edema.     

Visual disorders as key symptoms of ocular migraine

Vascular disturbance of the anterior visual pathways characterized by monocular visual experiences are sometimes caused by migraine. Retinal or ophthalmic migraine, a variant of complicated migraine, is distinctly rare. Two cases of female patients with ophthalmic migraine are reported. The relationships between the use of oral contraceptives and pregnancy are discussed.     

Bone turnover in postmenopausal women after withdrawal of estrogen/gestagen replacement therapy

Bone turnover before and after withdrawal of estrogen/gestagen treatment was studied in a randomized trial with 110 healthy female volunteers, who had passed a natural menopause 6 months to 3 years before the start of the study. Urinary excretion of intravenously injected 99m-technetium diphosphonate was measured as an index of bone turnover; plasma bone Gla protein and serum alkaline phosphatase were measured as indices of bone formation; and fasting urinary excretion of hydroxyproline and calcium were measured as estimates of bone resorption. During 2 years of hormone treatment, all variables decreased highly significantly (p less than 0.001) to a constant low level. Three months after withdrawal all variables increased highly significantly (p less than 0.001) towards, but not above, pretreatment and placebo levels. We conclude that withdrawal of estrogen/gestagen replacement therapy in postmenopausal women increases bone turnover, but not in excess of pretreatment values. This indicates that bone loss (after withdrawal) is similar to that seen in the placebo group and that a rebound phenomenon is unlikely.