Blood pressure lability in the sympathectomized rat

Intra-aortic blood pressure (BP) was measured in conscious rats after early chronic destruction of the peripheral sympathetic nervous system (SNS) with guanethidine. In sympathectomized rats, the mean level of BP was not different from that of control rats but its variability was markedly increased. These results indicate that functional integrity of the SNS is of primary importance for the short-term control of BP but is not essential for its long-term maintenance.     

Alteration of membrane permeability by amphotericin B

Amphotericin B (AmB) increased unidirectional Na transport and net transcellular sodium movements across the skin of the frog, Rana pipiens, when added to the solution bathing the corium side, but not from the outer epidermal surface. The AmB response was prevented with pretreatment with amiloride, ouabain and mucosal sodium substitution. Alteration in pH markedly reduced the permeability changes induced by AmB. AmB did not interfere with the increase in sodium transport induced by antidiuretic hormone. The present study demonstrates that AmB interacts with the skin of the frog, Rana pipiens, from the corium side specifically increasing transepithelial sodium transport. The increase in transport apparently occurs through the existing sodium pathway.     

Vers une approche physiopathologique des troubles de l’éjaculation

Seminal emission and sperm expulsion are under the control of both the sympathetic and parasympathetic outflows and also of the somatic innervation conveyed by the pudendal nerve. The 2 phases of ejaculation are reflexive with the reflexes handled at the thoraco-lumbar and sacral levels of the spinal cord. Such a spinal organization remains widely unknown. The role of various peripheral neurotransmitters has been evidenced including norepinephrine and acetylcholine and also peptidergic, purinergic i.e. ATP and nitric oxide. Stimulation of the seminal tract afferents play a crucial in the onset of ejaculatory mechanisms. Except for the dorsal nerve of the penis, there is a lack of information concerning these afferents. Several supraspinal centers i.e. hypothalamus, medial amygdala, pons and nucleus paragigantocellularis exert descending and ascending inhibitory and excitatory influences on spinal nuclei controlling emission and expulsion of sperm. Central neurotransmission responsible for this supraspinal control could involve serotonin, oxytocin and norepinephrine. In the light of the available anatomical and neurophysiological data, pathophysiological aspects of ejaculatory disorders are futher discussed. Premature ejaculation could be related to a periheral and central hypersentivity. Most of the other ejaculation abnormalities are likely mainly related to an impairment of the central mechanisms.     

3-Amino-6-methoxy-9-(2-hydroxyethylamino) acridine: A new fluorescent dye to detect mycoplasma contamination in cell cultures

A new fluorescent acridine orange derivative, 3-amino-6-methoxy-9-(2-hydroxyethylamino) acridine (AMHA), has been applied to Hela cells in order to set up appropriate conditions for the detection of mycoplasma contaminations. Since AMHA staining reveals intensely fluorescent nuclei and slight fluorescent cytoplasm, we can visualize and localize mycoplasma contamination on each cell. In combination with a shortened Chen's staining method (1977), AMHA should allow a better detection of mycoplasma in animal cell cultures than the well established Hoechst dye.