Cerebral 2-deoxyglucose accumulation in mice following chronic treatment with an ACTH4-9 analog, ORG 2766

The influences of fragments and analogs of ACTH/MSH upon recovery from nervous system injury

Post-injury treatment with some fragments and analogs of the adrenocorticotropic hormone (ACTH) can influence recovery after nervous system injury. This review considers both the successful and unsuccessful attempts to facilitate neural and behavioral recovery from nervous system damage via post-injury administration of these compounds. To date no single unifying explanation for the mixed results observed in animals prepared with forebrain injuries has been achieved. Several possible explanations for the variety of observations reported and several potentially productive avenues for future research are suggested.

Autoradiography of hypothalamic regions after acute hyperosmolarity in mice

Many regions around the third ventricle of the brain are thought to participate in the regulation of water intake. In this study we have visualized in acutely hyperosmolar mice the hypothalamic regions by using autoradiography and [14C]deoxyglucose as marker. By applying a recently published, inexpensive, calibrated photographic method for the analysis of the autoradiographs, we can show that the medial parts of the hypothalamus near the third ventricle increased their uptake of deoxyglucose in comparison with the lateral parts. Densitometric measurements confirmed the results. The results also indicate that parts of the medial hypothalamus, even those that are more caudal than the paraventricular nuclei, react to hyperosmolarity.

Melanocortins and fast axonal transport in intact and regenerating sciatic nerve

The effect of ACTH/MSH peptides on fast axonal transport along intact or regenerating sciatic nerve was examined following injection of tritiated leucine into the rat lumbar spinal cord. The rate of fast axonal transport was not significantly changed by treatment with ACTH/MSH(4-10), the ACTH(4-9) analog ORG 2766, hypophysectomy, or adrenalectomy. Fast axonal transport was unchanged in regenerating nerves and in regenerating, ACTH(4-10)-treated nerves. However, treatment with ORG 2766 in dosages of either 1 or 10 micrograms/kg/day IP for seven days significantly reduced (62% and 64%, respectively) the crest height of the fast axonal transport curve of intact sciatic nerve. The results suggest that the reported peptide-induced enhancement of nerve regeneration is not due to changes in the rate of fast axonal transport.

Effects of moderate ethanol sedation on brain regional 2-deoxyglucose uptake in alcohol-sensitive and alcohol-insensitive rat lines

Acute intraperitoneal ethanol administration (2 g/kg) decreased the accumulation of radioactivity after [14C]2-deoxy-D-glucose injection into grossly dissected brain regions of alcohol-sensitive (ANT) and alcohol-insensitive (AT) rat lines. In autoradiography, the balance of radioactivity uptake between different functional systems (as judged from relative optical density ratios) was changed after ethanol: especially in the ANT rats, areas associated with sensory input were damped but motor relay nuclei were relatively active, suggesting a tendency to motor overactivity relative to sensory input. The ANT rats furthermore showed slight relative damping of cortical associative areas and differences in limbic structures compared to the AT rats, which, provided that changes in the balance between brain regions with a decreased overall activity are meaningful, suggests that the higher level of ethanol-induced motor impairment of the ANT rats may be related to defects in their integration of sensory and motor processes.

Cerebral blood flow and brain shrinkage seen on CT during ACTH therapy

By means of the Doppler ultrasound method, the cerebral blood flow (CBF) was assessed in 21 children with epilepsy undergoing treatment with adrenocorticotrophic hormone (ACTH). The maximum reduction in the internal carotid velocity, as an index of CBF during therapy, was about 35 percent compared with the values before therapy. Furthermore, sequential computed tomography (CT) examinations of the same subjects were performed to evaluate the change in the area of the intracranial brain parenchyma during therapy. The maximum reduction in the parenchymal area during therapy was about 10 percent. This corresponds to a 20 percent reduction in CBF according to Poiseuille's law, however, the remaining reduction in CBF demonstrated by velocity measurement cannot be explained only by that mechanical vascular factor. From these findings, it is concluded that in order to elucidate the mechanism of the CBF reduction, physiological factors such as changes in metabolism during therapy should also be evaluated in addition to the mechanical and physical causes.