Cholinergic modulation of mesolimbic dopamine function and reward

The substantial health risk posed by obesity and compulsive drug use has compelled a serious research effort to identify the neurobiological substrates that underlie the development these pathological conditions. Despite substantial progress, an understanding of the neurochemical systems that mediate the motivational aspects of drug-seeking and craving remains incomplete. Important work from the laboratory of Bart Hoebel has provided key information on neurochemical systems that interact with dopamine (DA) as potentially important components in both the development of addiction and the expression of compulsive behaviors such as binge eating. One such modulatory system appears to be cholinergic pathways that interact with DA systems at all levels of the reward circuit. Cholinergic cells in the pons project to DA-rich cell body regions in the ventral tegmental area (VTA) and substantial nigra (SN) where they modulate the activity of dopaminergic neurons and reward processing. The DA terminal region of the nucleus accumbens (NAc) contains a small but particularly important group of cholinergic interneurons, which have extensive dendritic arbors that make synapses with a vast majority of NAc neurons and afferents. Together with acetylcholine (ACh) input onto DA cell bodies, cholinergic systems could serve a vital role in gating information flow concerning the motivational value of stimuli through the mesolimbic system. In this report we highlight evidence that CNS cholinergic systems play a pivotal role in behaviors that are motivated by both natural and drug rewards. We argue that the search for underlying neurochemical substrates of compulsive behaviors, as well as attempts to identify potential pharmacotherapeutic targets to combat them, must include a consideration of central cholinergic systems.     

Perceptions of Basic,Advanced, and Pediatric Life Support Training In a United States Medical School

Background

Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and Pediatric Advanced Life Support (PALS) are integral parts of emergency resuscitative care. Although this training is usually reserved for residents, introducing the training in the medical student curriculum may enhance acquisition and retention of these skills.

Objectives

We developed a survey to characterize the perceptions and needs of graduating medical students regarding BLS, ACLS, and PALS training.

Methods

This was a study of graduating 4^th-year medical students at a U.S. medical school. The students were surveyed prior to participating in an ACLS course in March of their final year.

Results

Of 152 students, 109 (71.7%) completed the survey; 48.6% of students entered medical school without any prior training and 47.7% started clinics without training; 83.4% of students reported witnessing an average of 3.0 in-hospital cardiac arrests during training (range of 0–20). Overall, students rated their preparedness 2.0 (SD 1.0) for adult resuscitations and 1.7 (SD 0.9) for pediatric resuscitations on a 1–5 Likert scale, with 1 being unprepared. A total of 36.8% of students avoided participating in resuscitations due to lack of training; 98.2%, 91.7%, and 64.2% of students believe that BLS, ACLS, and PALS, respectively, should be included in the medical student curriculum.

Conclusions

As per previous studies that have examined this topic, students feel unprepared to respond to cardiac arrests and resuscitations. They feel that training is needed in their curriculum and would possibly enhance perceived comfort levels and willingness to participate in resuscitations.     

Less is more? Stoma prolapse repair by linear stapler

Techniques in Coloproctology -