The stomach contents from a female Longman's beaked whale (Indopacetus pacificus), which stranded on the coast of Kagoshima Prefecture, Kyushu, Japan, were examined. This is the first specimen of this species from Japan and also its northern-most record. The remains collected from the stomach consisted of numerous cephalopod beaks and lenses and a large number of unidentified nematodes. Ninety-nine upper beaks and 69 lower beaks from squid species were collected from the stomach. The lower beaks were used to identify squid prey species; five species were identified: Taonius pavo, Onykia loennbergi, Onychoteuthis borealijaponica, Chiroteuthis picteti, and Histioteuthis inermis. Taonius pavo was the most common species and accounted for 84% of the total beaks. Distribution data for these squid species suggest that this whale fed in the epipelagic to mesopelagic zones in the western North Pacific off the southern part of Japan. Stomach morphology was also examined. The presence of a main stomach with three connecting chambers and one pyloric stomach compartment was confirmed. It appears that the morphology of this species' stomach is similar to that found in Tasmacetus and Ziphius. This is the first report on the food habits, stomach anatomy, and parasites of Longman's beaked whale and contributes to a better understanding of their biology.

In comparison with terrestrial animals, such as primates, there is limited empirical evidence for cooperative behavior in marine mammals under experimental conditions. In this study, we used a cooperative rope-pulling task to investigate how bottlenose dolphins (Tursiops truncatus) coordinate their behavior with a partner. Dolphins successfully learned and were able to perform the task, even when one subject started after the other. In the no-delay condition (i.e., both subjects sent at the same time), one pair of dolphins showed coordinated behaviors. When pairs were successful in solving the task in the delay condition (i.e., one individual sent later than the other), the initiators (i.e., first individual sent) were likely to wait for the follower to arrive, and the follower was likely to swim faster when the initiator did not wait and started pulling the rope alone. These coordinated behaviors might help resolve the given cooperative task. Our results suggest that bottlenose dolphins learn to coordinate their behaviors via trial and error and recognize the necessity of performing simultaneous actions with a partner to successfully accomplish cooperative tasks. In addition, both partners showed behavioral changes over many trials of no-delay and delay conditions, suggesting that bidirectional coordination occurred in the cooperative task.

Vasomotor effects of 5-hydroxytryptamine, histamine, angiotensin II, acetylcholine, noradrenaline, and bradykinin on the cerebral artery of bottlenose dolphin (Tursiops truncatus)

Recently, the number of aged people is increasing year by year, and it is getting a very important subject to treat properly the aged hypertensive patients. It is well known that cerebral blood flow is auto-regulated and maintained at constant level independent of the perfusion pressure (blood pressure). However, the lower break point of pressure-blood flow curve shifts to the right (high blood pressure side) in hypertensive patients, and sometimes drastic hypotension causes decrease of cerebral blood flow and results in cerebral ischemia. So that anti-hypertensive agents which have mild hypotensive action and do not decrease cerebral blood flow are preferable in these aplication.OPC -13340 (methy 3-phenyl-2(E)-propyl 1 , 4-dihydro-2, 6-dimethyl 4-(3-nitrophenyl)-3, 5-pyridine dicarboxylate) is a new long acting Ca antagonist (J ARDIOVASC PHARMACOL 15: 836, 1990) now undergoing clinical trials as an anti-hypertensive as well as an anti-anginal agent with once daily treatment. In this study, the hypotensive action and effects on the cerebral blood flow (CBF) of OPC-140were examined in normotensive Wistar rats (NTR) and aged spontaneously hypertensive rats (SHR) comparing with those of nicardipine and nimodipine.M aterials and Methods (1) Measurement of blood pressure: Male Wistar rats (15 weeks old) or SHR (52 weeks old) were anesthetized with sodium pentobarbital and cannulated into the abdominal aorta, and the blood pressure was measured in conscious state after 2 days of the surgery. m easurement of CBF: Male Wistar rats (10 weeks old) or SHR (50 weeks old) were anesthetized and hydrogen electrodes were implanted stereotactically into deep cerebrum and cortex. After more than 2 weeks, the CBF was measured in conscious state using hydrogen clearance method.(3) Drugs: Drugs were dissolved in 90% polyethylene glycol 400, and orally administered in the volume of 1ml/kg. The control experiments using solvent were carried out for both measurement. (4) Statistics: Multiple group comparisons were done by analysis of variance (ANOVA), followed by urkey's test using SAS program. Results and Discussion: In NTR, OPC-13340 (10mg/kg) significantly decreased systolic blood pressure (sBP) about 25mmHg, and increased CBF 50-60% in both cortex and deep cerebrum from 1hr to 8hr after administration (P<0.01). Nicardipine or nimodipine (30mg/kg) caused same extent of hypotension as OPC-13340, but increased CBF only 20-30%. On the other hand, in the case of aged SHR, OPC-13340 (1mg/kg) decreased sBP about 36mmH and tended to increase CBF 10-15%. OPC-13340 (3mg/kg) decreased sBP about 50mmHg, and in this case CBF did not increase. In contrast to this, nicardipine (3 and 10mg/kg) dropped the sBP about 35 and 50mmHg, respectively, and significantly decreased the CBF by 10-20% compared to prevalue. These data suggest following findins, (1) OC-13340 has more potent CBF increasing action comared with nicardipine or nimodipine at the dose of same hypotensive action in NTR.(2) In aged SHR, moderate hypotensive treatment does not dro CBF, b...