Distribution of neurokinin A-like and neurokinin B-like immunoreactivity in human peripheral tissues

Using specific radioimmunoassay and immunocytochemistry for neurokinin A (NKA) and neurokinin B (NKB), distribution and localization of the two peptides in human peripheral tissues were studied. Both NKA-like immunoreactivity (NKA-LI) and NKB-like immunoreactivity (NKB-LI) were present in the walls of the gut and gall bladder and in the pancreas. In the gut, the values for NKA-LI were 0.56-35.73 pmol/g wet weight, while those in pancreas and gall bladder were 0.64-0.68 and 0.36 pmol/g wet weight, respectively. The values of NKB-LI were 0.45-2.66 pmol/g wet weight in the gut, 0.93-1.65 pmol/g wet weight in the pancreas, and 0.30 pmol/g wet weight in the gall bladder. The immunocytochemical reactivity to both peptides was localized to ganglia of the submucosal and myenteric nerve plexuses in the gut wall, and to neurons in the muscle layer and mucosa of the gut wall. Weak but positive NKA-LI appeared in nerve cells of the pancreas, while NKB-LI was not detectable in the pancreas. Conversely, in the gall bladder wall, NKA-LI was undetectable while a very faint NKB-LI was found in the muscle layer. The localization of NKA corresponded closely to that of NKB in the tissues although the relative concentrations of the peptides varied from organ to organ.

[Eosinophil activation in acute asthma attacks evaluated by electronmicroscopic findings of eosinophils and the concentration of eosinophil cationic protein in sputum]

We evaluated the activation of eosinophils in the airways of patients with acute asthma attacks by measuring the concentration of sputum eosinophil cationic protein (ECP) and changes in the electron densities of the eosinophil specific granules in sputum. In six hospitalized patients with asthmatic attacks, sputum samples were collected for seven consecutive days after admission and were used for the evaluation of eosinophil activation. The concentration of sputum ECP, the incidence of changes in the electron densities of eosinophil specific granules and the severity of asthma attacks were highest on the day of admission and decreased in association with each other after treatment. A significant correlation was found between the concentration of sputum ECP and the incidence of changes in the electron densities of eosinophil specific granules. These findings suggest that the eosinophils in the airways are markedly activated and degranulated in asthma attacks.

Reduced somatostatin-like immunoreactivity in the brain of LEC rats with hepatic encephalopathy

Somatostatin-14-like immunoreactivity (S14LI) and somatostatin-28(1-12)-like immunoreactivity (S28(1-12)LI) in the brain of LEC (Long Evans Cinnamon) rats with hepatic encephalopathy were measured. Significant reduction of both S14LI and S28(1-12)LI was observed in the hypothalamus, medulla oblongata, striatum and spinal cord. Both of the immunoreactivities in the hypothalamus of these rats were approx. 50% of those in LEC rats without hepatic encephalopathy. The amounts of reduction of S14LI significantly correlated with those of reduction of S28(1-12)LI. No significant difference in gel chromatographic profiles of S14LI and S28(1-12)LI was observed between LEC rats with and without hepatic encephalopathy. These results suggest that the reduction of somatostatin-like immunoreactivity in LEC rats with hepatic encephalopathy may be caused by a decrease in production of prosomatostatin rather than altered degradation.

Reduced cholecystokinin in the brain of LEC rats with hepatic encephalopathy

Levels of cholecystokinin (CCK) immunoreactivity and distribution of CCK immunoreactive cells were studied in the cerebral cortex of LEC (Long Evans Cinnamon) rats with hepatic encephalopathy. CCK immunoreactivity in water extract of cerebral cortex of LEC rats with hepatic encephalopathy (n = 7) was 41.5 +/- 2.6 (mean +/- S.E.M. pmol/g wet wt.) and that of LEC rats without encephalopathy (n = 8) was 67.1 +/- 6.9, the difference being significant (P less than 0.01). CCK immunoreactive cells assessed by immunohistochemistry were also markedly decreased in the cortex of LEC rats with hepatic encephalopathy of stage IV. Thus, CCK reduction was observed in the cerebral cortex of LEC rats with hepatic encephalopathy which are provided as a model for analysis of the pathogenesis of acute hepatic encephalopathy.

Acetylcholine regulates pancreastatin secretion from the human pancreastatin-producing cell line (QGP-1N)

Studies were made of pancreastatin (PST) secretion from a human PST-producing cell line (QGP-1N) in response to various secretagogues. Cells with immunoreactivity for PST were observed in monolayer cultures of QGP-1N cells. Carbachol stimulated PST secretion and the intracellular Ca2+ mobilization concentration dependently in the range of 10(-6)-10(-4) M. The PST secretion and Ca2+ mobilization induced by carbachol were inhibited by atropine. The calcium ionophore (A23187) stimulated PST secretion. However, cholecystokinin and gastrin-releasing peptide did not stimulate either PST secretion or Ca2+ mobilization. Secretin also did not stimulate PST secretion. The glucose concentration in the culture medium had no effect on PST secretion. These results suggest that PST secretion is mainly regulated by acetylcholine through a muscarinic receptor, and that an increase in intracellular Ca2+ plays an important role in stimulus-secretion coupling in QGP-1N cells.

[Fundamental studies on measurement of the eosinophil cationic protein in sputum from patients with bronchial asthma]

One of the characteristics of patients with bronchial asthma is activation of eosinophils in the bronchi, which can be evaluated by measuring concentrations of the cationic granule proteins. Sputum seems to be the best material to evaluate the activation of eosinophils in the bronchi because it can be collected easily from the same patient every day even if he (she) has an asthmatic attack. Recently it has become possible to measure the concentration of the eosinophil cationic protein (ECP) thanks to the availability of the ECP RIA kit. However no fundamental studies have been carried out on the handling of sputum samples, and whether only ECP released into sputum is measured. We prepared supernatants of sputum samples according to the method of Gleich and others by adding the same volume of physiological saline, mixing it for one minute by a vortex mixer and centrifuging at 40000 Xg, 4 C, for 30 minutes. We found that the measurement of ECP is not inhibited by materials in sputum supernatants through a dilution test and a recovery test. We also found that the followings did not influence the measurement of ECP; the times of dilution, the duration from collection to handing of sputum, the solution added to sputum, and the gravity of centrifugation. In addition, it was suggested that only ECP released into sputum is measurable from the results of an electron microscopic study and the measurement of ECP after centrifugation following the addition of white blood cells to sputum.

The central pressor actions of a novel tachykinin peptide, gamma-preprotachykinin-(72-92)-peptide amide

Intracerebroventricular (i.c.v.) injections of a novel tachykinin peptide, gamma-preprotachykinin-(72-92)-peptide amide (neuropeptide gamma, NP gamma), caused dose-dependent increases in blood pressure. The NP gamma-induced pressor responses (1 microgram i.c.v.) were blocked by peripheral administration of pentolinium (10 mg/kg i.v.) and phentolamine (10 mg/kg i.v.), but were not inhibited by a vasopressin antagonist. These results suggest that central NP gamma increases the blood pressure via sympathetic nerve activity.

Renal cell carcinoma of the native kidney after renal transplantation. A case report and review of the literature

We report a patient with small renal cell carcinoma of the native kidney long after renal transplantation, which was considered to have developed before transplantation, and review the characteristics of renal cell carcinoma and acquired cystic disease following transplantation.

Distribution and localization of neurokinin A-like immunoreactivity and neurokinin B-like immunoreactivity in rat peripheral tissue

Using specific radioimmunoassays and immunocytochemistry for neurokinin A (NKA) and neurokinin B (NKB), distribution and localization of these peptides in rat peripheral tissues were studied. NKA-like immunoreactivity (NKA-LI) was present in highest levels of 15.7-23.9 pmol/g wet wt. and NKB-like immunoreactivity (NKB-LI) was in levels of 0.33-0.67 pmol/g wet wt., throughout the gastrointestinal tract involving stomach, duodenum, jejunum, ileum and colon. Immunocytochemical analysis of gastrointestinal tract revealed that NKA-LI and NKB-LI localized in ganglia of both the submucosal and myenteric plexuses as well as varicose neurons in the mucosa and the muscle layer of the small and large intestine. On the other hand, high levels of NKB-LI were observed in oesophagus (0.83 +/- 0.08 pmol/g wet wt.), adrenal (1.02 +/- 0.21), head of pancreas (0.73 +/- 0.06) and kidney (0.98 +/- 0.05). The present study shows the difference of localization of NKA-LI and NKB-LI in peripheral tissues and suggests that NKB may have some physiological role differing from that of NKA in peripheral tissues.

Pancreastatin-like immunoreactivity in urine

The concentration and molecular form of pancreastatin-like immunoreactivity (PST-LI) in urine of normal subjects and patients with noninsulin-dependent diabetes mellitus or chronic renal failure were examined. PST-LI output (mean +/- SEM) in urine of normal subjects was 74.6 +/- 8.5 pmol/day and 87.1 +/- 11.7 pmol/g creatinine. That in patients with noninsulin-dependent diabetes mellitus was 78.1 +/- 9.0 (SEM) pmol/day and 85.6 +/- 9.0 pmol/g creatinine and was not significantly different from that in normal subjects. Gel filtration analysis showed that PST-LI molecules excreted in urine of these two groups were smaller than human pancreastatin (43-52) (hPST-10) of C-terminal fragment. The PST-LI molecular forms were deduced to be nonbioactive from the result that hPST-10 did not inhibit pancreatic exocrine secretion. PST-LI excretion in patients with chronic renal failure was 258.5 +/- 62.9 pmol/day and 713.2 +/- 219.6 pmol/g creatinine. A molecular form corresponding to hPST-52 and a larger form eluted in the high mol wt region (approximately mol wt 15 K) were detected by gel filtration of urine from these patients, indicating that PST-LI is excreted in urine without degradation in patients with chronic renal failure. These results support the suggestion that the kidney may play an important role in PST degradation or metabolism.

Role of central tachykinin peptides in cardiovascular regulation in rats

The mechanisms of action of tachykinin peptides thought to be involved in central cardiovascular regulation were examined. Intracerebroventricular injections (i.c.v.) of tachykinin peptides caused dose-dependent increases in blood pressure and heart rate. The pressor responses to substance P (SP) (10 micrograms, i.c.v.) and neurokinin A (NKA) (10 micrograms, i.c.v.) were blocked by peripheral administration of pentolinium or phentolamine, and partially attenuated by adrenalectomy. In contrast, the only initial pressor response to the neurokinin B (NKB) analogue senktide (10 micrograms, i.c.v.) was blocked by pentolinium or phentolamine. The pressor response to senktide was inhibited by pretreatment with a vasopressin V1 receptor antagonist (d(CH2)5OMe(Tyr)AVP) (10 micrograms/kg, i.v.), and senktide (10 micrograms, i.c.v.) caused an increase in plasma vasopressin level. However, the vasopressin antagonist did not influence the SP- and NKA-induced pressor responses. These results suggest that central SP and NKA increase the blood pressure and heart rate via sympathetic nerve activity, whereas central NKB increases the blood pressure mainly via release of vasopressin from the hypothalamus.

Elevated plasma levels of pancreastatin (PST) in patients with non-insulin-dependent diabetes mellitus (NIDDM)

Pancreastatin (PST) is known as the peptide which inhibits first phase of glucose-stimulated insulin secretion. Fasting plasma PST levels and responses of PST after oral glucose ingestion in patients with non-insulin-dependent diabetes mellitus (NIDDM) were studied with human PST-specific radioimmunoassay. Fasting plasma PST in NIDDM patients was not different from healthy controls, although a slightly higher level of PST was observed in patients treated with sulfonylurea among NIDDM patients. No significant increase in plasma PST was observed after a glucose ingestion in healthy controls. In contrast, plasma PST levels in NIDDM patients rose significantly after glucose ingestion. These results suggest a possible pathophysiological role for PST in NIDDM.

Isolation and characterization of a tumor-derived human protein related to chromogranin A and its in vitro conversion to human pancreastatin-48

A protein with pancreastatin-like immunoreactivity has been isolated and purified from liver metastasis of a patient with insulinoma. NH2-terminal residue analysis, in conjunction with the use of antibodies that are specific for the C-terminal amide peptide of porcine pancreastatin, identified this protein as a 186-amino-acid protein corresponding to human chromogranin A-116-301 (the fragment corresponding to the positions from 116 to 301 of human chromogranin A). Digestion of this protein with trypsin yielded a 48-amino-acid peptide with the retention of full pancreastatin activity. Serum from patient with insulinoma contains a peptide specie(s) that comigrates with the 48-amino-acid pancreastatin, suggesting that this peptide might be a physiologically important circulation form of pancreastatin in humans. A sensitive radioimmunoassay was established using antibody developed against a synthetic 29-amino-acid peptide amide of pancreastatin. Immunocytochemical staining revealed that a major population of human pancreatic islet cells were immunoreactive to the antiserum but with varying intensity of staining. Pancreastatin-like immunoreactivity was not observed in exocrine acinar cells.

Plasma pancreastatin responses after intrajejunal infusion of liquid meal in patients with chronic pancreatitis

The plasma concentrations of pancreastatin and cholescystokinin (CCK), exocrine pancreatic responses, and gallbladder contraction following intrajejunal ingestion of 100 kcal/hr semidigested liquid meal (Clinimeal) were simultaneously studied in six controls and six patients with chronic pancreatitis. An intrajejunal infusion of Clinimeal resulted in significant rises of pancreastatin and CCK, which paralleled the pancreatic secretion and gallbladder contraction. On the other hand, an intrajejunal infusion of Clinimeal resulted in a delayed rise of pancreastatin and no rise of CCK in chronic pancreatitis. Pancreatic secretion did not increase, and gallbladder contraction was not induced in these patients. It is suggested that pancreastatin may play an important role in the regulation of intestinal phase of exocrine pancreas. The impaired pancreastatin and CCK release in chronic pancreatitis may be due to the inappropriate stimuli in the lumen, which is attributed to pancreatic exocrine dysfunction, or to disturbed physiological regulation between the pancreas and gastrointestinal tract.

Pancreastatin producing cell line from human pancreatic islet cell tumor

It has been characterized that cell line QGP-1 derived from human non-functioning pancreatic islet cell tumor produces human pancreastatin. Exponentially growing cultures produced 5.7 fmol of pancreastatin/10(6) cells/hr. Human pancreastatin immunoreactivities in plasma and tumor after xenografting with QGP-1 into nude mouse were 92.7 fmol/ml and 160.2 pmol/g wet weight, respectively. Immunocytochemical study revealed both chromogranin A and pancreastatin immunoreactive cells in the tumor. Gel filtrations of culture medium and tumor extract identified heterogenous molecular forms of PST-LI which eluted as large and smaller molecular species. These results suggest that plasma pancreastatin levels may be useful as a tumor marker of endocrine tumor of the pancreas, and the pancreastatin producing cell line may be useful for studies of the mechanism of secretions and processing of chromogranin A and pancreastatin.

[Relationship between presence of Creola bodies and airway hyperresponsiveness in patients with bronchial asthma]

It has recently been suggested that epithelial damage participates in the development of bronchial hyperresponsiveness. In this study we investigated the relationship between the presence of clusters of desquamated respiratory epithelial cells (Creola body. CrB) in sputum and airway responsiveness. Sputa were collected from asthmatic patients and acetylcholine inhalation tests were performed to assess airway responsiveness. Smears of 100 microliters of sputum were spread in pairs of two glass slides. One slide was stained with Papanicolaou's stain, the other with Giemsa stain. CrBs were detected on the whole glass slide stained with Papanicolaou's stain and the CrB score was determined by summing up the points given to each CrB on a glass slide according to the number of epithelial cells composing one CrB. The CrB score was significantly higher in patients with CrBs than in patients without CrBs. The patients with higher CrB score (CrB score greater than or equal to 6) had significantly greater number of eosinophils in sputa than the patients without CrBs. These results suggest the participation of damage to the respiratory epithelium in the development of airway hyperresponsiveness in bronchial asthma. The detection of CrBs is easy and we consider it clinically useful in the estimation of airway hyperresponsiveness.

Plasma pancreastatin-like immunoreactivity in various diseases

Plasma pancreastatin (PST)-like immunoreactivity in normal subjects and patients with various diseases was estimated by a RIA, using antiserum raised against a synthetic C-terminal peptide of human PST deduced from the sequence of human chromogranin-A. The mean level +/- SEM was 13.2 +/- 0.6 pmol/L in normal subjects, but was significantly higher in patients with chronic renal failure (526.7 +/- 48.5). An immunoreactive form corresponding to a human PST-like sequence [human chromogranin-A-(250-301)] and a larger form were detected by gel filtration of plasma from these patients, suggesting accumulation of the larger molecular form in these patients. A significant increase in PST-like immunoreactivity was also found in patients with liver cirrhosis (20.8 +/- 3.0 pmol/L), but not in patients with noninsulin-dependent diabetes mellitus, chronic pancreatitis, or pancreatic cancer. Elevated levels were found in 16 of the 21 patients with small cell lung carcinoma examined. High levels were also found in 3 of 11 patients with islet cell tumor.

High plasma pancreastatinlike immunoreactivity in a patient with malignant insulinoma

High levels of pancreastatinlike immunoreactivity were detected in the plasma (2.9 pmol/ml, greater than 200-fold the normal level), pancreas (2.9 nmol/g wet wt, greater than 450-fold the normal level), and liver (1.6 nmol/g wet wt) of a patient with pancreatic insulinoma with metastasis to the liver by a sensitive and specific radioimmunoassay for human pancreastatin. Antiserum was produced against the C-terminal fragment of human pancreastatin-(24-52), which was synthesized according to the sequence of human chromogranin A corresponding to that of pancreastatin. With the antiserum, intense immunocytochemical staining was detected in the tumors. Sephadex G-50 gel filtration showed that the tumors and plasma contained two molecular forms of pancreastatinlike immunoreactivity--a molecular form coeluted with synthetic human pancreastatin-52 and a larger molecular form (Mr approximately 12,000-15,000). The smaller form eluted in the same position as synthetic human pancreastatin-52 on reverse-phase high-performance liquid chromatography.

Isolation and characterization of a tumor-derived human pancreastatin-related protein

A protein with pancreastatin-like immunoreactivity has been isolated and purified from liver metastasis of a patient with insulinoma. NH2-terminal sequence analysis in conjunction with the use of antibodies specific for the C-terminal structure of pancreastatin identified this protein as a 186-amino acid residue protein corresponding to human chromogranin A-116-301. Using a sensitive radioimmunoassay it was found that serum from the patient with insulinoma contains two peptide species; one comigrates with the 186-amino acid residue pancreastatin and the other the 48-residue pancreastatin.

Central pressor actions of neurokinin B: increases in neurokinin B contents in discrete nuclei in spontaneously hypertensive rats

The regional distributions of neurokinin B-like immunoreactivity and substance P-like immunoreactivity in the central nervous system in spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto rats (WKYs) were examined. The distribution of neurokinin B-like immunoreactivity in WKYs was not exactly the same as that of substance P-like immunoreactivity. The neurokinin B-like immunoreactivity contents of the supraoptic nucleus of the hypothalamus and the caudal part of the nucleus tractus solitarii were higher in SHRs than in WKYs. Injections of selective neurokinin B receptor peptides, senktide (suc-[Asp6,Me-Phe8]-substance P6-11) and [Pro7]-neurokinin B, into the lateral brain ventricle of the normotensive rats caused dose-dependent increases in the blood pressure, and blockade of peripheral vascular vasopressin receptors reduced these pressor responses, but did not affect the substance P-induced pressor response. These findings suggest that the novel tachykinin peptide, neurokinin B has an important role in central pressor action in rats.

[A successful arterial switch operation for the transportation of the great arteries with posterior aorta--with special reference to its anatomical features and possibility of the indication of the Jatene procedure]

A five months old infant with the transposition of the great arteries with posterior aorta undergoing arterial switch operation is reported. A pre-operative diagnosis of the transposition of the great arteries with posterior aorta, subarterial ventricular septal defect, anterior pulmonary artery, bilateral conus and fibrous continuity between aortic and mitral valve was made. This diagnosis was confirmed by the open heart surgery. The ventricular septal defect was subaortic from the transected aortic aspect, and the infundibular and trabecular septum was aligned. For these reasons, this subarterial ventricular septal defect was easily closed transaortically. The right coronary artery arose from the left sinus and the left coronary artery from the posterior sinus, so the coronary arterial pattern of this patient was a Shaher type 9. And in addition, another small ostium located in the left sinus gave rise to an additional small branch. Translocation of the coronary arteries was performed. The new pulmonary trunk was reconstructed to the right pulmonary artery so as not to compress the coronary artery and distort the great arteries. This patient was restudied three months after the repair. The right to left ventricular systolic pressure ratio was 0.42 and no pressure gradient was present between the right ventricle and the right pulmonary artery. But a moderate aortic regurgitation was detected. This was caused by deformity of the aortic sinus of valsalva. Only 28 patients with the transposition of the great arteries with posterior aorta were reported in the literature, but there were no reports on the successful surgical treatment for its rare anomaly, to our knowledge.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular roles of tachykinin peptides in the nucleus tractus solitarii of rats

Unilateral removal of the afferent fibers of the IXth and Xth cranial nerve (nodose ganglionectomy) caused significant decrease in the content of substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in the nucleus tractus solitarii (NTS) of rats. Microinjection of SP (1 ng) or NKA (10-100 ng) into the NTS caused prompt, transient hypotension and bradycardia, suggesting that SP and NKA may be neurotransmitters of the baroreceptor reflex in the NTS. NKB-like immunoreactivity (NKB-LI) was also detected in the NTS of rats by radioimmunoassay, but its content in the NTS was not affected by unilateral nodose ganglionectomy. The microinjection of 1-10 ng of suc-[Asp5, Me-Phe8]-SP(6-11) (senktide, a selective neurokinin B receptor peptide) into the NTS caused long-lasting hypertension and tachycardia. These results indicate that NKB may also be a neuromodulator on cardiovascular responses in the NTS.

Marked depression of brain cholecystokinin and vasoactive intestinal polypeptide levels in Eck fistula dogs

Cholecystokinin-like immunoreactivity (CCK-LI) and vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) were measured in the brain of Eck fistula dogs and dimethylnitrosamine (DMN)-treated dogs which were prepared as experimental models of hepatic encephalopathy (HE). Significant reduction of CCK-LI was observed in all cortical regions of Eck fistula dogs, especially in parietal and occipital cortex (approximately 40% of control values). In DMN dogs, CCK-LI was reduced in the temporal, parietal and occipital cortex (65%, 47% and 51% of control values, respectively). Significant reduction of VIP-LI was also observed in the occipital cortex of both Eck fistula and DMN dogs (75% and 70% of control values, respectively). These data were compared with the concentrations of tyrosine and phenylalanine, precursors of false neurotransmitters suggested as causing HE. Phenylalanine was significantly increased in all areas of cortex of both models. Tyrosine was also significantly increased in frontal, parietal and occipital cortex of Eck fistula dogs, and in temporal, parietal and occipital cortex of DMN dogs. However, reduced amounts of these peptides did not correlate with increased amounts of the aromatic amino acids in these models. The results imply that reduced levels of CCK and VIP may be elicited by a mechanism distinct from that inducing increase of false neurotransmitters.

Bioactivity of human pancreastatin and its localization in pancreas

Synthetic human pancreastatin and its C-terminal fragment were first evaluated with respect to the biological activity on the insulin secretion in the isolated rat islets. Both these pancreastatins inhibited glucose-stimulated insulin secretion at a concentration of 100 nM. The relative molar potency of human pancreastatin compared to that of porcine pancreastatin was equivalent. The pancreastatin-reactive cells were widely located in the islets of Langerhans, and not observed in exocrine acinar cells by immunocytochemistry using human pancreastatin C-terminal specific antibody. These results suggest that human pancreastatin may modulate endocrine function of the pancreas, especially insulin secretion.

Establishment of highly specific radioimmunoassays for neurokinin A and neurokinin B and determination of tissue distribution of these peptides in rat central nervous system

Highly specific radioimmunoassays (RIAs) for neurokinin A (NKA) and neurokinin B (NKB) were developed. Antisera were produced by the procedure which involved immunization with NKA or NKB, both conjugated with keyhole limpet hemocyanin, and treatments with a tolerogenic conjugate of kassinin and a copolymer of D-glutamic acid and D-lysine (D-GL) to inhibit the production of cross-reactive antibodies against common C-terminal region of tachykinins. Cross-reactivities of anti-NKA antiserum (R704), thus produced, with NKB, kassinin, eledoisin were 12.6%, 10.6% and 11.5%, respectively. This was in sharp contrast with those of antiserum obtained from the rabbit not treated with kassinin-D-GL, these values corresponding to 129.0%, 42.5% and 94.4%, respectively. The cross-reactivities of R704 with substance P and physalaemin were 0.3% and 1.5%, respectively. This antiserum also bound 35.6% of neuropeptide K which contains NKA at its C-terminal. More importantly, anti-NKB antiserum (R707) obtained by the above tolerizing regimen was highly specific for NKB and the cross-reactivities with NKA, neuropeptide K, kassinin and other tachykinins were all less than 0.001%. RIAs using these specific antisera allowed us to measure directly NKA and NKB in tissue extracts without their fractionation by chromatography prior to RIAs. Measurements of immunoreactive NKA and NKB in different rat brain regions and spinal cord revealed that they are present with various ratios (NKA/NKB: 1.1-9.9) depending on the region.