Cerebellar cGMP varies with motor function and respiratory gas exchange.

Paralysis of rats with d-tubocurarine decreased cerebellar guanosine 3': 5'-cyclic monophosphate (cGMP) content to about one third of normal values when arterial oxygen and carbon dioxide were maintained at normal values. In addition, altering arterial carbon dioxide tensions in these paralyzed rats revealed that cerebellar cGMP was inversely related to arterial carbon dioxide tension, and that this relationship could be blunted by increasing arterial oxygen tension. It is possible that part of the decrease in cerebellar cGMP content by CNS depressants observed in several species in many laboratories may be simply secondary to the decreased motor function and/or respiratory depression produced.

Behavioral and prolactin responses to 5-hydroxytryptophan in rats treated during development with 5,7-dihydroxytryptamine.

The serotonin precursor, 5-hydroxytryptophan (5-HTP), can induce a behavioral syndrome characterized by rigidity, splayed feet, tremor, head weaving, salivation and forepaw treading. This response to 5-HTP was markedly potentiated in adult rats treated intracisternally with 5,7-dihydroxytryptamine (5,7-DHT) during development. Prevention of the 5,7-DHT-induced reduction of brain norepinephrine with pargyline or desipramine did not diminish the potentiation of 5-HTP, suggesting that noradrenergic fibers are not contributing to the altered 5-HTP response.

Lead exposure during infancy permanently increases lithium-induced polydipsia.

Lead (200 milligrams per kilogram) was administered daily by intubation to Long-Evans rats on days 3 through 30 of life. Thirty to 180 days after cessation of lead administration, the lead-treated rats were consistently more polydipsic after lithium administration (2 millimoles per kilogram per day) than were pair-treated controls. Lithium increased the plasma renin activity equally in both the lead treated and the control groups.

Evaluation of the effects of nerve growth factor and anti-nerve growth factor on the development of central catecholamine-containing neurons.

Intracisternal NGF or anti-NGF has been found to produce no long-term major alterations in central norepinephrine (NE) or dopamine levels when administered to neonatal rats. While NGF and anti-NGF were found to produce significant changes in brain NE content within one week of treatment, changes in central NE were no longer detectable at 30 days of age. Modification of the growth response of the central adrenergic neurons following 6-OHDA treatment was also not affected by NGF or anti-NGF when evaluated 3 weeks after treatment.

The occurrence of multiple forms of cytochrome P-450 in hepatic microsomes from untreated rats and mice.

The hepatic microsomes of rat and mice were subfractionated by the procedure of Dallner. When a 1.3 M sucrose lower layer was used for the two-step discontinuous gradient, no differences in spectral characteristics were noted between subfractions, though the smooth fractions (SER) had higher oxidative activity towards the substrates tested.