Area postrema lesions produce feeding deficits in the rat: effects of preoperative dieting and 2-deoxy-D-glucose

To investigate the possible role of the area postrema (AP) in the control of food intake and body weight, male albino rats were divided into four groups: (a) animals dieted to 80% of their original body weights prior to receiving AP lesions, (b) nondieted animals with AP lesions, (c) animals dieted to 80% prior to receiving sham lesions, and (d) nondieted animals with sham lesions. Lesions of the AP in nondieted rats resulted in hypophagia, hypodipsia and body weight loss followed by recovery of normal intake and maintenance of body weight at a fixed percentage of the sham operated animals' weight. Reducing body weight prior to surgery led to body weight maintenance levels equivalent to those of the nondieted groups. We also tested the animals for sensitivity to glucoprivation caused by intraperitoneal injections of 2-deoxy-D-glucose (2-DG). Injections of 2-DG produced hyperphagia in sham lesioned rats, but not in rats with AP lesions. Our data suggest that the effects of AP lesions on intake and body weight are similar, in several important respects, to the lateral hypothalamic feeding syndrome and to the effects of subdiaphragmatic vagotomy. We discuss the results with respect to hierarchical levels of neural circuitry involved in controlling feeding behavior.

Fiber pathways associated with cerebellar self-stimulation in the rat: a retrograde and anterograde tracing study

Intracranial self-stimulation (ICSS) was obtained from an area of cerebellum just rostro-ventral to the fastigial nucleus. The acquisition of cerebellar ICSS was slow, although this depended in part on the type of operant task required. The afferent and efferent fiber connections of the region of cerebellum supporting ICSS were identified using silver-degeneration and horseradish peroxidase tracing techniques. Two major pathways, one ascending to the ventromedial thalamus and one descending to the paramedian reticular formation and the region of the solitary nucleus, are discussed as possible substrates of ICSS at sites in the cerebellum as well as from other pontine and medullary regions.

Regulation of rat liver fructose 2,6-bisphosphatase

An enzyme activity that catalyzes the hydrolysis of phosphate from the C-2 position of fructose 2,6-bisphosphate has been detected in rat liver cytoplasm. The S0.5 for fructose 2,6-bisphosphate was about 15 microM and the enzyme was inhibited by fructose 6-phosphate (Ki 40 microM) and activated by Pi (KA 1 mM). Fructose 2,6-bisphosphatase activity was purified to homogeneity by specific elution from phosphocellulose with fructose by specific elution from phosphocellulose with fructose 6-phosphate and had an apparent molecular weight of about 100,000, 6-phosphofructo 2-kinase activity copurified with fructose 2,6-bisphosphatase activity at each step of the purification scheme. Incubation of the purified protein with [gamma-32P]ATP and the catalytic subunit of the cAMP-dependent protein kinase resulted in the incorporation of 1 mol of 32P/mol of enzyme subunit (Mr = 50,000). Concomitant with this phosphorylation was an activation of the fructose 2,6-bisphosphatase and an inhibition of the 6-phosphofructo 2-kinase activity. Glucagon addition to isolated hepatocytes also resulted in an inhibition of 6-phosphofructo 2-kinase and activation of fructose 2,6-bisphosphatase measured in cell extracts, suggesting that the hormone regulates the level of fructose 2,6-bisphosphate by affecting both synthesis and degradation of the compound. These findings suggest that this enzyme has both phosphohydrolase and phosphotransferase activities i.e. that it is bifunctional, and that both activities can be regulated by cAMP-dependent phosphorylation.

Yersinia arthritis: a clinical, immunological, and family study of 2 cases

We describe 2 patients who presented with yersinia arthritis within a period of 5 months in Leicester. Both were HLA B27 positive. Arthritis followed 2 to 3 weeks after pneumonia, abdominal pain, dysuria, and evidence of hepatic involvement in the first case, and dysuria and conjunctivitis in the second. Immunological studies showed the presence of IgM, IgG, and IgA antibodies at a significant level against Yersinia enterocolitica serotype O:3 in serum and synovial fluid, and immune complexes in the serum of the first case and synovial fluid of both. Arthropathy resolved after 16 weeks in the first case and 12 weeks in the second, the latter requiring systemic corticosteroids. Family studies revealed psoriatic spondylarthritis in the brother, and bilateral sacroiliitis in the mother of the second case. Both were HLA B27 positive. These are the fourth and fifth reported cases of yersinia arthritis in Britain. We believe the condition is probably underdiagnosed and that yersiniosis should be considered as a possibility in otherwise unexplained arthritis.

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Siblings of the retardate: An adolescent group experience

This paper describes a preventive-therapeutic program for normal adolescent siblings of retardates in which siblings met regularly with two psychologist co-leaders to discuss their thoughts and feelings about having a retarded sibling. The program was designed to explore a model of clinical functioning with normal children whose siblings create special problems for the family, with the goal of establishing effective preventive programs for such children.