SUMMARYThe effect of bradykinin on afferent cardiac sympathetic nerve fibers has been examined. Using anesthetized dogs, the action potentials of the fi bers were derived from either the 2nd or 3rd thoracic communicating ramus of the left side. Excitation of the afferent fibers was observed following administration of bradykinin acetate dissolved in physiological saline on the left ventricular wall. The minimum concentration required for excitation was 50-100ng/ml. The fibers were excited rhythmically synchronous with myocardial contraction and/or relaxation. However, no significant augmentation of myocardial contraction was produced by the agent. Bradykinin-induced excitation of the fibers was significantly reduced by pretreatment with acetylsalicylic acid. The results suggest bradykinininduced sensitization of the receptor sites of the afferent fibers for normal modality of left ventricular motion. 2) This substance is the most powerful of all the algesic agents.3) It causes pain in humans when it is applied to a blister base on the skin or when injected into somatic and visceral arteries4)-7) and elicites the pseudaffective response in animals when injected into the coronary artery.1) However, it is unclear whether this agent activates the afferent cardiac sympathetic nerve fibers which subserve nociception of the heart.8)-10) Our studies have been undertaken to examine the effect of bradykinin acetate solutions on afferent sympathetic nerve fibers which originated in the left ventricular wall.

Cycloheximide is one of the antibiotics that inhibit protein synthesis in most eukaryotic cells. We have found that a yeast, Candida maltosa, is resistant to the drug because it possesses a cycloheximide-resistant ribosome, and we have isolated the gene responsible for this. In this study, we sequenced this gene and found that the gene encodes a protein homologous to the L41 ribosomal protein of Saccharomyces cerevisiae, whose amino acid sequence has already been reported. Two genes for L41 protein, named L41a and L41b, independently present in the genome of S. cerevisiae, were isolated. L41-related genes were also isolated from a few other yeast species. Each of these genes has an intron at the same site of the open reading frame. Comparison of their deduced amino acid sequences and their ability to confer cycloheximide resistance to S. cerevisiae, when introduced in a high-copy-number plasmid, suggested that the 56th amino acid residue of the L41 protein determines the sensitivity of the ribosome to cycloheximide; the amino acid is glutamine in the resistant ribosome, whereas that in the sensitive ribosome is proline. This was confirmed by constructing a cycloheximide-resistant strain of S. cerevisiae having a disrupted L41a gene and an L41b gene with a substitution of the glutamine codon for the proline codon.

SUMMARY Supine plasma concentration of norepinephrine (PNE), epinephrine (PE), and aldosterone (PA), plasma renin activity (PRA), and blood volume (BV) were measured in 25 normotensive and 11 hypertensive patients with biopsy-proven glomerulonephritis who had serum creatinine concentrations of less than 1.6 mg/dl, and in 20 normotensive control subjects. PNE and PE were measured according to the trihydroxyindol method using high pressure liquid chromatography. Renal clearances of p-aminohippurate (C PAH ) and endogenous creatinine (Ccr) were also determined. Age, BV, and 24-hour urinary excretion of sodium were not significantly different in the three groups. Although all the measured variables were comparable between the control subjects and the normotensive nephritic patients, blood pressure, PNE, PE, PRA, and PA were significantly higher and C PAH and Ccr were significantly lower in the hypertensive nephritic patients than in the normotensive nephritic patients or the control subjects. In the pooled nephritic patients, mean blood pressure was significant-

Excitation of aferent cardiac sympathetic neruejbers during coronary occlusion. Am. J. Physiol. 226(5) : 1094-1099. 1974.-The effect of coronary artery occlusion on afferent sympathetic nerve fibers whose receptor sites are in the left ventricular wall has been examined. Action potentials were recorded from fibers of either the second or third thoracic communicating ramus of the left side of anesthetized dogs. Excitation occurred in both myelinated A6 and unmyelinated C fibers in 29.2 & 16.4 s after coronary occlusion. The A6 fibers