L. Frattola

Effects of bromocriptine on central dopaminergic receptors

Abstract Bromocriptine injected to rats induces an increase of cAMP levels in the striatum in vivo. The time course of this increase is very similar to that of apomorphine. However bromocriptine does not stimulate striatal dopamine-sensitive adenylate cyclase but surprisingly antagonized the activation of this enzyme elicited by dopamine. Possible hypotheses on various sites of action of the drug are discussed.

A case of lipid storage myopathy with carnitine deficiency: Biochemical and electromyographic correlations

Histochemical, biochemical and electromyographic studies were performed in a case of carnitine deficiency in serum and in muscle. Clinical features include proximal muscle weakness, predominant type I fiber impairment, excess of triglycerides and moderate glycogen accumulation in muscle. No abnormalities of palmityl CoA synthetase, carnitine palmityl transferase, carnitine acetyl transferase and lipase were evidenced. An interesting EMG decremental pattern was recorded. Correlations between electromyographic and biochemical findings are considered. A clinical improvement, a normal plasma carnitine level and a normal response at EMG repetitive stimulation were found after carnitine treatment.

Effect of common carotid occlusion on beta-adrenergic receptor function in cerebral microvessels.

beta-adrenergic receptors were measured in cerebral microvessels of gerbils and rats after ligature of the right or left common carotid artery. The results indicate a decrease in the number of beta-adrenergic receptors in brain microvessels of both ipsilateral and contralateral hemispheres. This event may reflect altered patterns of the neuronal regulation of brain microvasculature and may be related to cerebrovascular alterations which are concomitant with ischemia. Furthermore, the results show that the decrease in beta-receptor density is more pronounced in the left hemisphere, independently on the side of carotid occlusion. This finding suggests that microvessel function in the left side of the brain is more vulnerable to hypoxia effects.

Time-related asymmetric changes of brain microvessel beta-adrenergic receptors in the two hemispheres after carotid occlusion.

The effect of short term and long term ischemia induced by right carotid occlusion was studied on beta-adrenergic receptor function in rat cerebral microvessels. The results show a different time-dependent responsiveness of the two hemispheres to ischemia, with a pronounced and more persistent decrease in the number of capillary beta-receptors in the left side of the brain. The data suggest the existence of asymmetries in the control of brain microvasculature which may mediate the different time-course of beta-receptor changes in response to ischemia.

Glial Brain Tumors Lack Microvascular Adrenergic Receptors

In human and animal brain microvessels beta-adrenergic receptors have been identified which are suggested to subserve the regulation of capillary function in both physiological and pathological conditions. Brain tumors are supplied by vessels that differ from those supplying normal cerebral tissue in various structural and functional parameters. In order to study the characteristics of brain tumor microcirculation, we have investigated the presence of beta-adrenergic receptors in capillaries isolated from different types of neoplasms using the specific radioligand 125I-iodocyanopindolol (ICYP). The microvessels were isolated and prepared by albumin flotation and glass bead filtration from normal and pathological tissues. No ICYP-specific binding was detected in the microvessels of tumors of glial origin, while capillaries obtained from meningiomas and neurinomas showed, like the normal brain, a specific binding of the radioligand. The data indicate that the regulation of capillary function in glial tumors differs from that of normal cerebral tissue and extraparenchymal tumors, thus indicating an impaired control of the vascular permeability.

Guanylate cyclase in human brain tumors: regulation of cellular growth.

Summary Guanylate cyclase activity measured in different brain tumors has been found higher in meningiomas and oligodendrogliomas in comparison with normal cortex. The apparent Km of GTP for guanylate cyclase is considerably lower in all tumor tested in comparison to normal cortex. The data may be in line with the assumption that cGMP is one of the intracellular mediators triggering cell growth.

Scoliosis and Parkinson's Disease-Reply

In Reply.— As requested in the letter by Marsden and Duvoisin, we report further clinical notes on our patient described in theArchives(36:246-248, 1979). Rigidity, tremor, and akinesia first appeared on the right side, and the severity of the disease had always been prevalent on the same side. In the untreated state, the patient showed a lean of the trunk directed ipsilaterally to initial and major parkinsonian symptomatology. Scoliosis was not found on roentgenologic examination of the spinal column. The asymmetrical posture with lean to the right side was more apparent when the patient was standing or sitting in a chair for a long period. In these conditions, the patient never showed a tendency to slump to the left, as expected by Marsden and Duvoisin. It is important to note that the abnormalities of motor behavior (twisting movements and falling to the right side) started in the patient after long treatment

ERGOT DERIVATIVES IN DYSKINETIC AND DYSTONIC DISORDERS

SUMMARY CF 25-397 is an ergot derivative with a different behavioral and neuro chemical profile compared to other ergot drugs, such as bromocriptine and lergotrile. In human studies CF 25-397 has been administered to patients with on-off attacks. In this condition a reduction in the fluctuations of the clinical state and a decrease in dyskinesias were observed in all patients. However rigidity and akinesia were increased. CF 25-397 has been also administered to patients suffering dyskinesias and dystonia of various origin. In these patients the drug significantly decreased symptoms score.