Temperature-Induced Alterations in Rabbit Testicular Contractility in Vitro

Abstract

Rabbit testicular contractions and intratesticular pressure were recorded in vitro as temperature was increased from 33 to 38°C. The response of the testicular capsule to several physiological agents was quantified at 35, 37 and 38°C. A corresponding increase in intratesticular pressure was observed with each contraction. Uniform intratesticular pressures developed in normal spontaneous autorhythmic testicular preparations. The force of capsular contractions increased slightly from 33 to 35°C, but decreased markedly with temperatures above 35°C. Intratesticular pressure increased linearly with increased force of contractions to a maximum of 142 mg of tension. As intratesticular pressure increased, the amplitude of contractions decreased. Marked irregularities in force and frequency of contractions occurred with temperatures above 38°C. Increasing testicular temperature from 35 to 37°C and from 37 to 38°C both markedly reduced the effectiveness of acetylcholine by 58 and 71%, serotonin by 52 and 71%, epinephrine by 41 and 45%, PGF_2α by 37 and 54%, histamine by 33 and 54% and bradykinin by 29 and 43%, respectively, in their ability to increase tone of the capsule.

Key Words:

• Testis
• Rabbit
• Contractility
• Temperature
• Intratesticular pressure
• Acetylcholine
• Serotonin
• Epinephrine
• PGF_2α
• Histamine
• Bradykinin.