Baroreceptor activation reduces reactivity to noxious stimulation: implications for hypertension.

The hypothesis was tested that an acute rise of blood pressure may reduce reactivity to noxious stimuli through a baroreceptor-mediated reduction of cerebral arousal. When blood pressure was raised by an infusion of phenylephrine, rats showed less running to terminate or avoid noxious stimuli than during saline infusions. This effect was not seen in rats with denervated baroreceptors. The results suggest that a rise of blood pressure could have motivational consequences significant for human hypertension.

Treatment of the agoraphobic dental patient.

The dental-phobic patient is rarely motivated to seek treatment. When this type of patient does, it is difficult to perform the dental work without repeated interruptions due to the high anxiety being displayed. Many dental phobics are actually agoraphobic, and this further complicates the matter. The agoraphobic dental patient mislabels any physiologic changes that are experienced as a prelude to disaster, or horrific consequences, and something there is no control over. This type of patient looks to depend on "safe" places (like home) and "safe" people (like spouses and doctors). The physiologic changes that are perceived may be induced pharmacologically (for example, numbness and tingling from the lidocaine, imbalanced blood gases due to hyperventilation), physically (for example, tilt of the dental chair, pressure in the mouth), or cognitively (autonomic excitation due to negative thoughts). The inability to mitigate the physiologic changes or symptoms confirms the patient's irrational belief that disaster is inevitable. Two basic considerations must be given priority when treating agoraphobic dental patients. These are: (1) providing them with a sense of being in control of the situation and/or their symptoms, and (2) training them to relabel or reinterpret their symptoms objectively as nervousness, or some simple and explainable physiologic change that should be present. Therefore, teaching agoraphobic dental patients cognitive-behavioral procedures such as relaxation and cognitive-restructuring techniques works quite well. Both will help to prevent, or reduce to a manageable level, the symptoms, and result in successful dental work.

A chronic arterial catheter and low compliance system for recording blood pressure and heart rate from the rat.

A procedure for cannula construction, surgical implantation, and utilization is presented for recording arterial blood pressure and heart rate from the renal artery of unanesthetized mobile rats. The method involves unilateral nephrectomy, but the animals recover quickly and remain in excellent health. The cannula requies minimal maintenance; it has been used in cardiovascular experiments to make multiple periodic arterial blood pressure recordings. Patency for 2 mo or longer is common.